Luminous Landscape Forum

Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: smahn on March 28, 2015, 01:44:21 pm

Title: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: smahn on March 28, 2015, 01:44:21 pm
I could use help in researching a replacement for this combo. I'm not doing true 1:1 macro, more like 1:4, with studio flash and a tripod. So high ISO, image stabilization, and burst rate are of little value to this application.

I don't want to move up to medium format, so FF or mirrorless. No AA filter. 16MP and up is fine. But I want to consider the chip/lens combo.

I get pretty good results with the current combo but it takes a lot of PP to get there. I'm always straddling between "sharp  enough" and artifacts. Most Raw processors default sharpening positions don't come close. And I don't think it's a bad lens, I get similar results with a Nikon 105 micro.

So I know about the Nikon 810, I've got my eye on that. If I go that direction what lens would I pair with it? And are there mirrorless options I should consider? I'm not opposed to spending less.  ;)

Thanks
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Hans Kruse on March 28, 2015, 02:16:13 pm
You don't say which Canon 100mm macro as there are two: The old one and the new with IS.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: smahn on March 28, 2015, 02:24:52 pm
The non IS.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Hans Kruse on March 28, 2015, 02:30:02 pm
At least you should try the IS version as it is better optically. Known as a very very good lens http://www.dpreview.com/lensreviews/canon_100_2p8_is_usm_c16/6
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: pegelli on March 28, 2015, 03:01:18 pm
Two legendary macro lenses I've see are the Voigtlander APO lanthar 125 mm / f2.5 and the Minolta APO Macro 200 mm / f4.
They're both renowned for their sharpness as well as pleasant rendering of the out of focus area.
Sharpness isn't everything to achieve a pleasing picture.

Both would be easily mounted on the 36 MP Sony a7R

But it would mean buying into a completely new system, unless you can find the Voigtlander lens for the Canon mount (don't know if they ever produced it with that mount)
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Hans Kruse on March 28, 2015, 03:57:35 pm
Why should older lenses designed long before modern technology almost automatically be better the newest lens designs? I come across this all the time and can't find a good reason other than nostalgia :) I'm not discounting that there are good older lenses, but unless a comparison and measurements are done, the case may be quite weak.

The easy way to find is to rent.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: muntanela on March 28, 2015, 04:04:08 pm
I'm happy  with a Leitz R Elmarit 100 apo macro :-* on D800E, stunning sharpness and colours, no traces of CA.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: pegelli on March 28, 2015, 04:58:08 pm
Why should older lenses designed long before modern technology almost automatically be better the newest lens designs?
I never said they were better, and certainly not automatically. It just were some suggestions of good macro lenses to look at and see if he likes them for what he is looking for.
I also suggest you do some research, especially on the Voigtlander, and be ready to be surprised  ;) Maybe less so on the Minolta.

Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Hans Kruse on March 28, 2015, 05:04:21 pm
I never said they were better, and certainly not automatically. It just were some suggestions of good macro lenses to look at and see if he likes them for what he is looking for.
I also suggest you do some research, especially on the Voigtlander, and be ready to be surprised  ;) Maybe less so on the Minolta.



Sorry and maybe I'm just tired of seeing reference to amazing old lenses :) I don't know the Voightlander myself as macro was a certain relatively short phase in my photography. But research and testing is important in finding the best lenses.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Jack Hogan on March 28, 2015, 05:38:38 pm
This current thread (http://forum.luminous-landscape.com/index.php?topic=98645.0) seems to touch on a few.

Jack
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: BernardLanguillier on March 28, 2015, 07:34:09 pm
You may find some usefull info here as well: www.lenscore.org

It shows that the Canon 100mm f2.8 is good, a bit behind its Zeiss and Nikon counterparts, but not by much.

Overall, the Schneider Mako-Symar 90mm T/S seems to be the best macro lens among those they measured (but it's very expensive), the Zeiss 100mm f2.0 is #2 and much cheaper. I own the Zeiss and have had good results, even if it is not as well color corrected as the latest non macro Zeiss wonder boys.

One photograph shot on the D3x 5 or 6 years ago:

(https://farm5.staticflickr.com/4079/4915121241_db382fe720_o.jpg)

Cheers,
Bernard
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: David Sutton on March 28, 2015, 08:34:29 pm
Sorry and maybe I'm just tired of seeing reference to amazing old lenses :) I don't know the Voightlander myself as macro was a certain relatively short phase in my photography. But research and testing is important in finding the best lenses.
Many older lenses were made with glass containing lead, which may have given them an advantage. I used a Contax 35-70 on my Canon which was gave stunningly better contrast and sharpness over any Canon lens I owned. Not as good however on the chromatic aberration front, and I don't recall it giving better colour rendition. And I lost auto focus and exposure. Swings and roundabouts.
David
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: John Koerner on March 28, 2015, 09:18:56 pm
They're all behind this one: http://www.bhphotovideo.com/c/product/837868-REG/Sigma_180mm_f_2_8_APO_Macro.html
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: John Koerner on March 29, 2015, 12:52:30 am
The Sigma 180 mm is ahead of the Canon 100 and 180 on pretty much everything, and is roughly-equal to the Zeiss on the most important elements (resolution, contrast, color, bokeh).

RESOLVING POWER:
Zeiss 100: 1189
Sigma 180: 1078
Canon 100L: 813

CONTRAST:
Zeiss 100: 1087
Sigma 180: 1017
Canon 100L: 851

COLOR:
Sigma 180: 964
Zeiss 100: 951
Canon 100L: 870

BOKEH:
Zeiss 100: 1062
Sigma 180: 1050
Canon 100L: 925

(Numbers derived from here (http://www.lenscore.org).)

While the Zeiss barely edges out the Sigma in some important elements, it's not by much, and there are several elements where the Sigma is much more desirable than the Zeiss (true 1:1 magnification not 1:2; Image Stabilization; Tripod Collar; REACH).

The Zeiss does have a clear advantage for precision focusing with 720° of rotation compared to 270° in the Sigma (compared to mere 180° in the Canon).

If you don't care about true 1:1, and are doing precision MF only, the Zeiss may be the way to go.

But if you want the flexibility of positioning, and true 1:1 magnification, then the tripod collar, the reach, the true 1:1, and the IS of the Sigma place it in a far more desirable position than the Zeiss ... with neck-n-neck qualities.

Jack
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: BernardLanguillier on March 29, 2015, 05:15:24 am
But if you want the flexibility of positioning, and true 1:1 magnification, then the tripod collar, the reach, the true 1:1, and the IS of the Sigma place it in a far more desirable position than the Zeiss ... with neck-n-neck qualities.

Your new Sigma is definitely a nice lens.

This being said, initial statement of the OP: "I'm not doing true 1:1 macro, more like 1:4".

Cheers,
Bernard
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Bart_van_der_Wolf on March 29, 2015, 05:29:02 am
I could use help in researching a replacement for this combo. I'm not doing true 1:1 macro, more like 1:4, with studio flash and a tripod. So high ISO, image stabilization, and burst rate are of little value to this application.

I don't want to move up to medium format, so FF or mirrorless. No AA filter. 16MP and up is fine. But I want to consider the chip/lens combo.

Hi,

Other than throwing some cash at it and get better quality lenses, which only hurts the wallet, there seems to be an issue with Raw conversion/sharpening as well. The reason for wanting an AA-less camera is not clear to me, because the aliasing artifacts that produces will also complicate Capture sharpening. Maybe throwing money at improving the hardware won't solve your problem entirely?

Quote
I get pretty good results with the current combo but it takes a lot of PP to get there. I'm always straddling between "sharp  enough" and artifacts. Most Raw processors default sharpening positions don't come close. And I don't think it's a bad lens, I get similar results with a Nikon 105 micro.

Now this may be because you are attempting to wring more performance out of the lens than there is, but the postprocessing tools/skills may also need to be improved. Default sharpening settings are notoriously stupid, they do not take the camera settings into consideration, while the aperture and magnification factor usually pretty much dictate the required settings and are therefore relatively simple to set up correctly.

Cheers,
Bart
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Conner999 on March 29, 2015, 07:23:34 am
From my own experience, going off memory in some cases (some lenses since sold) and strictly IMHO:

Leica 100 APO - legendary, sharp, great color correction. Manual stop-down
Mamiya 120/4 ULD - love it, sharp, very good color correction, manual stop-down.
Leica 60mm macro - great lens, not apo, but decent color corr. Manual stop-down
Zeiss 100/2 - sharp, great bokeh, not so great color correction for the $$$. If was APO would be perfect 100 manual focus macro for Nikon/Canon.
Zeiss 50/2 - nice, but my Leica 60 was equal or better IQ for, at time, far less $$
Zeiss 135/2 APO - IF it gives you know magnification you want (can't recall) - perfect all around. Should never have sold mine.
Nikon 105 VR - very nice, but not on par with many on this list. Great to have if need AF (which I do for work), but not a 1st choice if AF not needed.
CV 125 APO - sharp, great color correction & bokeh,  LONG focus throw. Price has gone nuts vs. other options last couple of years (should have kept mine ;>)
CV 90 3.5 APO. Not macro, but has close focus. Fantastic IQ if gives you mag you need.
Nikon 60 G - very sharp, nice bokeh, strong vignetting WO and color correction is not fantastic vs. other manual focus options

No experience with Sigma or Tamron, but some of their units do have a great rep. If you want to spend large $$, the Coastal Optics 60 macro is very well regarded.

Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: muntanela on March 29, 2015, 10:26:41 am
The Leitz Elmarit apo macro R 100  too has an unendliches focus throw...
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: BAB on March 29, 2015, 10:58:35 am
If your pixel peeping for sharpness may I ask what percentage od the entire frame is being used for your image.
Because if you cropping and only using part of the frame that changes how you play the game and essintly what tools the game dictates you must use to achieve your desired look. The choice at that point is medium format!
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: smahn on March 29, 2015, 12:35:49 pm
If your pixel peeping for sharpness may I ask what percentage od the entire frame is being used for your image.
Because if you cropping and only using part of the frame that changes how you play the game and essintly what tools the game dictates you must use to achieve your desired look. The choice at that point is medium format!

Please elaborate.

I'm often only using half the frame, for a few reasons. 1) Depth of field, 2) Working distance*, 3) Less downsampling deterioration.

I don't need autofocus, but I do like auto aperture, or whatever that's called when the lens stops itself down whe taking the image. Less hands on the lens for focus stacking.

* Working distance is an intimate dance. It has to be just right. Far enough back that my lens isn't inside my set/tent, but not so far back that I can't reach the set from the side of the camera. Point being, I find the 100mm range ideal, I think 180-200 would put me too far away.

Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: smahn on March 29, 2015, 01:02:59 pm
Hi,

Other than throwing some cash at it and get better quality lenses, which only hurts the wallet, there seems to be an issue with Raw conversion/sharpening as well. The reason for wanting an AA-less camera is not clear to me, because the aliasing artifacts that produces will also complicate Capture sharpening. Maybe throwing money at improving the hardware won't solve your problem entirely?

Well I'm asking about the lens/chip combination. I don't know how explore the hardware beyond that. But in chip sample comparisons I tend to see better sharpness/detail/resolving power from non AA chips. But I'd be happy to see examples that demonstrate otherwise. And if you can demonstrate that the 5d2 is as good as it gets, I'd be happier still.  :)


Now this may be because you are attempting to wring more performance out of the lens than there is, but the postprocessing tools/skills may also need to be improved. Default sharpening settings are notoriously stupid, they do not take the camera settings into consideration, while the aperture and magnification factor usually pretty much dictate the required settings and are therefore relatively simple to set up correctly.

Cheers,
Bart

I don't use default sharpening settings, I use, to varying degrees: LR at max amount and zero detail, and sometimes high/max detail and low amount. Photo Ninja. Topaz Focus. Topaz Detail. Smart Sharpen at high and low radii. USM at high and low radii. Which is simply to say, I'm not ignoring the PP.

I'm not trying to put one piece of hardware over another, or hardware over technique. I'm looking to refine and evolve all of these. I just thought it would be easier to start at the root: the hardware at the capture itself (which this thread was about). Then the PP would come after and be tailored to it.

Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: John Koerner on March 29, 2015, 01:37:48 pm
Your new Sigma is definitely a nice lens.

This being said, initial statement of the OP: "I'm not doing true 1:1 macro, more like 1:4".

Cheers,
Bernard


True. Which actually makes a 180mm even more ideal, because you have so much more ability to isolate the background when you don't have to be close enough for 1:1.



_____________________




Please elaborate.

* Working distance is an intimate dance. It has to be just right. Far enough back that my lens isn't inside my set/tent, but not so far back that I can't reach the set from the side of the camera. Point being, I find the 100mm range ideal, I think 180-200 would put me too far away.



This doesn't make any sense. If you're cropping, then why not just frame your shot correctly by getting the correct distance to begin with?

The difference in minimum focus distance, between the original Canon 100mm and the Sigma 180, is about 6".
In other words, what is "not close enough" in the 100mm (causing you to crop closer-in) would be about the perfect distance with the 180mm, requiring no crop at all.

So it sounds like the exact reverse is true: a 180 mm would put you at exactly the right distance to frame your shot properly, no-crop-needed.

Jack
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Bart_van_der_Wolf on March 29, 2015, 02:41:49 pm
Well I'm asking about the lens/chip combination. I don't know how explore the hardware beyond that. But in chip sample comparisons I tend to see better sharpness/detail/resolving power from non AA chips. But I'd be happy to see examples that demonstrate otherwise. And if you can demonstrate that the 5d2 is as good as it gets, I'd be happier still.  :)

There is only a small difference in resolution between cameras with and without AA-filters. The difference that is there, is caused by higher micro-detail contrast of the AA-less versions, but that also comes with a higher risk of (color) moiré and other aliasing artifacts which will make sharpening more difficult.

The biggest jump in resolution will come from upgrading the sensor to a higher MP version. That will immediately pull more resolution out of the current lenses. Upgrading the lens quality then will add additional resolution. The sensor resolution boost is the bigger factor in an improved system resolution.


Quote
I don't use default sharpening settings, I use, to varying degrees: LR at max amount and zero detail, and sometimes high/max detail and low amount. Photo Ninja. Topaz Focus. Topaz Detail. Smart Sharpen at high and low radii. USM at high and low radii. Which is simply to say, I'm not ignoring the PP.

The aperture you used has a significant effect on the Radius you should use in all sharpening tools, regardless of the camera/lens used, and regardless of the subject you shoot. There is a direct relationship between the two, so with different apertures you should use different radii. The better sharpening tools use deconvolution sharpening for Capture sharpening. Then you can add subject dependent Creative sharpening as a second and separate operation.

Quote
I'm not trying to put one piece of hardware over another, or hardware over technique. I'm looking to refine and evolve all of these. I just thought it would be easier to start at the root: the hardware at the capture itself (which this thread was about). Then the PP would come after and be tailored to it.

Yes, that's clearer now.

As said above; Sensor, Lens, post-processing, in that order, will have the largest impact on your results. But of course they all matter for the final result.

Cheers,
Bart
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: smahn on March 29, 2015, 03:18:03 pm
So it sounds like the exact reverse is true: a 180 mm would put you at exactly the right distance to frame your shot properly, no-crop-needed.

You like the 180, perhaps I'll try it. I've been doing this for some years though and all I can say is I'm comfortable at the distance the 100 puts me. Again, though, I may try it.

But I want to be clear about something, I'm not trying to add resolution via megapixels. Most of my deliverables are 2000x2000 px or less. So I'm looking to increase the sharpness at a given image size.

Downsampling is a whole another issue I need to explore. I get caught in a trap where the client wants most images for exploded view web (about 1600x1600 px) and for some shots wants high res for ads. I generally work at about 2,200-2,500 px on the long edge for my master image and down sample to 1600 for jpegs. The problem is the downsample (and any post downsample sharpening) can really mess with the fine details. So I'm really not looking to start with larger MP images. In fact, with larger MP sensors I might crop more.

FWIW, much of the fine detail I'm talking about is tight lines of diamond facets. If a non AA filter would cause those lines to be jagged that would be a problem.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: John Koerner on March 29, 2015, 03:32:37 pm
You like the 180, perhaps I'll try it. I've been doing this for some years though and all I can say is I'm comfortable at the distance the 100 puts me. Again, though, I may try it.

I've used a 100 mm for years also, but prefer the 180mm (Canon's at first, now Sigma) for a number of reasons already mentioned.



I've been doing this for some years though and all I can say is I'm comfortable at the distance the 100 puts me. Again, though, I may try it.

You've not given the 180mm a chance, so really you're "comfortable" doing what you're doing, only because you've not tried an alternative.

The very fact you admit to cropping means you're not operating at the correct distance. The distance may be comfortable for your hands/convenience, but by virtue of the fact you're cropping this means you're not close enough to maximize a full image; you're throwing away part of what you take.

If you had a 180mm at the same distance you keep your 100mm, then you would be zoomed-in more and (1) would not have to crop and (2) would have a bigger/better image than a cropped equivalent.

The Sigma 180mm is a better lens in every way the word "better" can be applied to a lens (resolving power, contrast, color, bokeh, etc.) ... and its reach would allow you to frame your shot from the same position you use the current old 100, but where you could now utilize the full image, thus allowing you more detail and printing size options than using the lens you now have.

That's my $0.02 ...

Jack
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: smahn on March 29, 2015, 05:47:45 pm
John, using the whole image is not advantageous in my situation. But thanks.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: bjanes on March 29, 2015, 06:00:14 pm
Now this may be because you are attempting to wring more performance out of the lens than there is, but the postprocessing tools/skills may also need to be improved. Default sharpening settings are notoriously stupid, they do not take the camera settings into consideration, while the aperture and magnification factor usually pretty much dictate the required settings and are therefore relatively simple to set up correctly.

Bart,

I am familiar with your recommendations regarding adjusting the radius in the sharpening tool and have used your slanted edge tool with a couple of my lenses. However, I don't know how to factor in the magnification. The effective aperture does decrease (larger f/number) when one focuses closer and the magnification increases, but with the newer lenses with a built in computer chip, the effective f/number is reported in the exif and is automatically set by the camera. What further needs to be done?

Cheers,

Bill
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: John Koerner on March 29, 2015, 06:39:00 pm
John, using the whole image is not advantageous in my situation. But thanks.

Sure. But a crop is a compromise, never an advantage.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: smahn on March 29, 2015, 06:51:29 pm
Sure. But a crop is a compromise, never an advantage.

Sure, until FF becomes a disadvantage, which can happen with heavy downsampling.

But lets not argue. You gave some good advice, I hope to have the opportunity to see if it suits my use.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Bart_van_der_Wolf on March 29, 2015, 06:56:02 pm
Bart,

I am familiar with your recommendations regarding adjusting the radius in the sharpening tool and have used your slanted edge tool with a couple of my lenses. However, I don't know how to factor in the magnification. The effective aperture does decrease (larger f/number) when one focuses closer and the magnification increases, but with the newer lenses with a built in computer chip, the effective f/number is reported in the exif and is automatically set by the camera. What further needs to be done?

Hi Bill,

At normal focusing distances of say 10 feet or more the differences between nominal and effective aperture are small. And as you say, it may not be immediately clear from the Exif data (unless one knows what it is that is reported) what the effective aperture is. It depends on the specific camera system, but I suppose one could compare infinity focus with close-up focus and Aperture priority metering to see what is recorded.

At close-up focusing of e.g. a 1:4 magnification ratio, the required exposure time increases by approx. a factor of (1+1/4)^2, or with the same exposure time the effective aperture number increases with a factor of (1+1/4).

A more precise figure depends on the lens design, and for the aperture it is:
Effective Aperture = Aperture x (1 + Magnification/pupilFactor) .
The pupil factor is the Exit/Entrance pupil diameter ratio, which can be estimated by looking through the lens from both ends and measuring the apparent diameter of the pupils.

This effective aperture is what determines the diffraction that dominates the differences in required sharpening radius at narrower apertures. I've shown it before, but attached is the measured blur, and required radius to restore sharpness, for my EF 100mm f/2.8L Macro IS lens. It might be that other lenses show similar characteristics and resulting settings, but one can only be sure by measuring it, e.g. with the slanted edge method (http://forum.luminous-landscape.com/index.php?topic=68089.msg538932#msg538932).

Cheers,
Bart
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: smahn on March 29, 2015, 07:14:56 pm
There is only a small difference in resolution between cameras with and without AA-filters. The difference that is there, is caused by higher micro-detail contrast of the AA-less versions, but that also comes with a higher risk of (color) moiré and other aliasing artifacts which will make sharpening more difficult.

Bart, I would appreciate if you could expand on this. Much of my work is, if there is a such a thing, high end web based. I don't need huge megapixel resolution, I need really sharp and micro detailed smaller/medium size images.

Here's a google image search for pave diamond:

http://tinyurl.com/on9nna6

Imagine one of those bracelets with a thousand diamonds and the client wanted every facet of every diamond distinct. it takes a high degree of resolving power even if it's ultimately not a high res image. (I fear the term resolution is getting confusing. I'm more talking about being able to discern (resolve) the finest lines through the lens and at the chip, not how many megapixels the resulting file yields.)

Now you maae the point that an non AA chip will give better micro contrast at the outset, but that an AA chip may yield a sharper final by allowing more aggressive sharpening. Other than me buying/renting two cameras to test side by side (which I may ultimately do, but which two?) do you have examples or other means to illustrate which might serve me better?

The best comparison tool I've found so far is here (though I've not searched far and wide):

http://www.dpreview.com/previews/nikon-d810/9

And the Nikon d810 just looks better than the competition, though I haven't looked into the lenses and processing used.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Bart_van_der_Wolf on March 30, 2015, 03:21:44 am
This effective aperture is what determines the diffraction that dominates the differences in required sharpening radius at narrower apertures. I've shown it before, but attached is the measured blur, and required radius to restore sharpness, for my EF 100mm f/2.8L Macro IS lens. It might be that other lenses show similar characteristics and resulting settings, but one can only be sure by measuring it, e.g. with the slanted edge method (http://forum.luminous-landscape.com/index.php?topic=68089.msg538932#msg538932).

One more thing to add.

These specialized lenses can use different methods to achieve the close-up focusing capability, and also other lenses use internal focusing groups that may change the focal length and for that matter the entire optical performance. It then becomes a bit tricky to blindly apply corrected measurements that were made at a vastly different distance/magnification.

The difficulty with calibration of the close-up focusing performance of a lens is that the quality of the test target also becomes much more important. I'll try to do a test today if I get a chance, and determine the blur characteristics in close-up scenario's. For that I'll use a slanted edge made from self-adhesive pvc material (white on black, to reduce the contrast a bit), cut with a sharp knife for a clean sharp edge. Other possibilities are to use the edge of a razor blade, although then there are some issues with reflection.

Cheers,
Bart
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Bart_van_der_Wolf on March 30, 2015, 04:13:15 am
Bart, I would appreciate if you could expand on this. Much of my work is, if there is a such a thing, high end web based. I don't need huge megapixel resolution, I need really sharp and micro detailed smaller/medium size images.

Yes, your objective is becoming clearer now. The added number of pixels are not the real reason for the higher resolution though, although that can be achieved by down-sampling (but you seem to have some issues with that, which we can also solve). It also has to do with how dense the sensels are packed, and denser sampling will pull more resolution out of any lens.

Quote
Here's a google image search for pave diamond:

http://tinyurl.com/on9nna6

For those I'd assume that DOF restrictions are your main cause for loss of resolution, assuming that the entire object must be in focus. For such objects it is almost unavoidable to do focus stacking at the lens' best aperture. However, in the plane of best focus (which is much thinner than the DOF range), the previous sharpening observations still stand, i.e. aperture determines resolution and therefore the sharpening radius that's required to restore resolution. Focus magic or Topaz InFocus are dedicated deconvolution sharpening tools, and Topaz Detail also offers deconvolution, and other tools that address the different levels of detail.

Quote
Imagine one of those bracelets with a thousand diamonds and the client wanted every facet of every diamond distinct. it takes a high degree of resolving power even if it's ultimately not a high res image. (I fear the term resolution is getting confusing. I'm more talking about being able to discern (resolve) the finest lines through the lens and at the chip, not how many megapixels the resulting file yields.)

Here down-sampling can be your friend, not your enemy, so I wouldn't eliminate high MP cameras from your shortlist. Not only will the DOF limited resolution improve up to the limits of pixel size, but also (photon shot- and read-)noise will be reduced which would make sharpening easier because of a higher signal to noise in the image.

Quote
Now you make the point that an non AA chip will give better micro contrast at the outset, but that an AA chip may yield a sharper final by allowing more aggressive sharpening. Other than me buying/renting two cameras to test side by side (which I may ultimately do, but which two?) do you have examples or other means to illustrate which might serve me better?

It's hard to find direct comparisons, but it's a basic Digital Signal Processing (DSP) fact of life; discrete sampling introduces aliasing artifacts if there is finer detail than the sampling interval. Now in the case of the pavé seting of diamonds, there is an added complexity that may even help, and that's the DOF requirements. Since it will be hard to get sufficient DOF at the maximum resolution, the defocus will act as a kind of AA-filter. But that still leaves the in-focus edges susceptible for aliasing, so it remains a tricky approach (especially with a Bayer CFA that can lead to false color artifacts caused by aliasing).

Quote
The best comparison tool I've found so far is here (though I've not searched far and wide):

http://www.dpreview.com/previews/nikon-d810/9

And the Nikon d810 just looks better than the competition, though I haven't looked into the lenses and processing used.

From the specs the D810 certainly looks capable, and there are probably quite decent close-up or macro/micro lenses available. I have no experience with how well e.g. tethering works with the Nikons. My personal experience is mostly with Canons and they have good tethering capabilities, and lots of tools that support e.g. focus stacking like Helicon Remote (http://www.heliconsoft.com/heliconsoft-products/helicon-remote/). The D810 is apparently also supported by Helicon Remote, so that leaves those options open.

Cheers,
Bart
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: NancyP on March 30, 2015, 11:03:43 am
This is for studio shooting. The upcoming Canon 50 MP camera might give you the best detail. Canon sensors lag on dynamic resolution, but that's a non-issue for studio work. I can also see that 180mm is overkill - how blurred do you need a white background? Do you currently focus stack? If so, how do you move your lens or sensor?
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: ErikKaffehr on March 30, 2015, 11:47:08 am
Hi,

As Bart said, with macro work DoF and Diffraction always fight each other. The best way to achieve fine detail may be to use focus stacking.

This very dead fly photographed using a Photar 25/2.5 and it has been stacked from something like 30 exposures:
(http://echophoto.dnsalias.net/ekr/Articles/Stacking/2015-01-14-22_24_18_ZS_PMax_small.jpg) (http://echophoto.dnsalias.net/ekr/Articles/Stacking/2015-01-14-22_24_18_ZS_PMax.jpg)

Full size image: http://echophoto.dnsalias.net/ekr/Articles/Stacking/2015-01-14-22_24_18_ZS_PMax_small.jpg

I guess the Canon 100/2.8LII macro is quite good, but any lens will be killed by diffraction when stopped down to much, and shooting close up normally adds extension so real aperture may be much smaller than the aperture shown on the camera.

The Sigma 150 and 180 mm tele macros are very well corrected for axial chroma, the stuff that yields magenta/green out of focus areas, at least according to Photozone tests.

Best regards
Erik

This is for studio shooting. The upcoming Canon 50 MP camera might give you the best detail. Canon sensors lag on dynamic resolution, but that's a non-issue for studio work. I can also see that 180mm is overkill - how blurred do you need a white background? Do you currently focus stack? If so, how do you move your lens or sensor?
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: smahn on March 30, 2015, 12:15:43 pm
Do you currently focus stack? If so, how do you move your lens or sensor?

Ok, I'm glad you asked. Bart's responses have convinced me I shouldn't really improve my techniques with what I have before I shell out big bucks. And whatever I pick up in the process can be utilized with the better eq too.

So my dirty little secret is that I typically shoot at f16 on a lens that goes to f32, so two stops from max. Working in a production environment, I have to work quickly. For each item, I shoot it from a few angles with lighting tweaks. Then the client chooses which he likes best. It's very cumbersome to focus stack all these "working shots", not knowing which will be the final. If the item is a ring or bracelet, it's often okay (if not attractive) to have the front in focus and the back soft. So at f16, and not using the whole sensor, I can often get the DOF in one pop. So there is, I confess, a degree of diffraction I'm working against.

But for each shoot there's always a couple I do have to stack, in which case I do about 3 focus slices at f16, focusing using the lens, and combining in LR with the plugin Enfuse.

Bart, you are the sharpening maestro, but I have to admit sometimes this sharpening stuff gets a little too mathy for my little brain. I love technique, but in the pursuit of art not science. I'm more like a chef trying a recipe than an immunologist looking for a cure. All of which is to say, are you able to point me to a couple of concise tutorials that would benefit me for overcoming diffraction, and perhaps automating focus stacking? If you (or anyone) can point me to something that would be great. I just want the recipe though without the math and science. If it passes the eye test that's good enough for me.

I'm on a Mac, fwiw.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Jack Hogan on March 30, 2015, 01:23:36 pm
This very dead fly...

Ugh, Erik, a dr. Hagen's morbid dream  :-\
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Jack Hogan on March 30, 2015, 01:24:34 pm
Sensor, Lens, post-processing, in that order, will have the largest impact on your results. But of course they all matter for the final result.

Amen to that.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: ErikKaffehr on March 30, 2015, 04:20:19 pm
Hi,

What I have seen, mostly, is that there is little difference between decent quality lenses once you stop down to f/8, or so. Aberrations have settled down and diffraction starts to dominate. Now, keep in mind that with close ups, real aperture may be much smaller than marked on the lens, in the old times if the lens was set at f/16 the real aperture would be f/32 at 1:1, now days with floatings element and internal focusing the effect may be much less.

With the good sharpening methods we have at hand, much of the contrast lost to diffraction can be regained. So it may be a good idea to focus on optimising post processing.

Best regards
Erik


Ok, I'm glad you asked. Bart's responses have convinced me I shouldn't really improve my techniques with what I have before I shell out big bucks. And whatever I pick up in the process can be utilized with the better eq too.

So my dirty little secret is that I typically shoot at f16 on a lens that goes to f32, so two stops from max. Working in a production environment, I have to work quickly. For each item, I shoot it from a few angles with lighting tweaks. Then the client chooses which he likes best. It's very cumbersome to focus stack all these "working shots", not knowing which will be the final. If the item is a ring or bracelet, it's often okay (if not attractive) to have the front in focus and the back soft. So at f16, and not using the whole sensor, I can often get the DOF in one pop. So there is, I confess, a degree of diffraction I'm working against.

But for each shoot there's always a couple I do have to stack, in which case I do about 3 focus slices at f16, focusing using the lens, and combining in LR with the plugin Enfuse.

Bart, you are the sharpening maestro, but I have to admit sometimes this sharpening stuff gets a little too mathy for my little brain. I love technique, but in the pursuit of art not science. I'm more like a chef trying a recipe than an immunologist looking for a cure. All of which is to say, are you able to point me to a couple of concise tutorials that would benefit me for overcoming diffraction, and perhaps automating focus stacking? If you (or anyone) can point me to something that would be great. I just want the recipe though without the math and science. If it passes the eye test that's good enough for me.

I'm on a Mac, fwiw.

Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Bart_van_der_Wolf on March 30, 2015, 06:20:38 pm
Ok, I'm glad you asked. Bart's responses have convinced me I shouldn't really improve my techniques with what I have before I shell out big bucks. And whatever I pick up in the process can be utilized with the better eq too.

So my dirty little secret is that I typically shoot at f16 on a lens that goes to f32, so two stops from max. Working in a production environment, I have to work quickly. For each item, I shoot it from a few angles with lighting tweaks. Then the client chooses which he likes best. It's very cumbersome to focus stack all these "working shots", not knowing which will be the final. If the item is a ring or bracelet, it's often okay (if not attractive) to have the front in focus and the back soft. So at f16, and not using the whole sensor, I can often get the DOF in one pop. So there is, I confess, a degree of diffraction I'm working against.

Hi,

I suspected something like that. Diffraction will spoil a lot of the fun, but narrow apertures may be required to get enough DOF in a single shot. If that's the case, then you need a good deconvolution sharpening tool, like e.g. FocusMagic. It works best, like all deconvolution tools, when noise is modest, so make sure the exposure level is high enough that you don't need to push in postprocessing.

Quote
But for each shoot there's always a couple I do have to stack, in which case I do about 3 focus slices at f16, focusing using the lens, and combining in LR with the plugin Enfuse.

Bart, you are the sharpening maestro, but I have to admit sometimes this sharpening stuff gets a little too mathy for my little brain. I love technique, but in the pursuit of art not science. I'm more like a chef trying a recipe than an immunologist looking for a cure. All of which is to say, are you able to point me to a couple of concise tutorials that would benefit me for overcoming diffraction, and perhaps automating focus stacking? If you (or anyone) can point me to something that would be great. I just want the recipe though without the math and science. If it passes the eye test that's good enough for me.

Diffraction is a fact of physics/life. the best you can do is avoid it by using wider apertures and/or by using something like FocusMagic to restore some of the seemingly lost resolution. Topaz InFocus can also restore resolution, but it is more finicky and very quickly produces artifacts when the settings are sub-optimal. FocusMagic is a bit more robust for this restoration stuff.

I understand the workspeed requirements, although they will work against getting the best quality. It also means that you'll have to automate as much as possible. Helicon Focus with Helicon Remote can help with the stacking, 'Remote' can calculate and automatically take the required number of shots when you set the front and rear positions that need to be in focus, and then Helicon Focus will stitch the results, if necessary from Raws.

Your hesitation towards down-sampling can be solved if you e.g. use Lightroom which does a decent job . The downsampling will also allow to shoot with more detail where the subject is in focus, and it will 'sharpen' the out-of-focus parts a bit, which were caused by the DOF limitations.

Cheers,
Bart
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: smahn on March 30, 2015, 08:04:51 pm
Ok then. I do use LR to downsample and I shoot at low ISO and ETTR, so those are handled.

I will thoroughly investigate Focus Magic and the Helicon products.

That's very simply and concise information. Thank you for that.

And thanks to everyone who replied. I will reread the entire thread now to digest it a second time.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: NancyP on March 31, 2015, 11:44:03 am
I always learn something here. That Focus Magic program looks to be worth a try.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Jack Hogan on April 01, 2015, 03:19:20 am
It works best, like all deconvolution tools, when noise is modest, so make sure the exposure level is high enough that you don't need to push in postprocessing.

On deconvolving noisy images, I gotta remember to try this (https://www.youtube.com/watch?v=p2aln2dLKdw) Topaz DeNoise approach on low ISO images.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Bart_van_der_Wolf on April 01, 2015, 03:37:28 am
On deconvolving noisy images, I gotta remember to try this (https://www.youtube.com/watch?v=p2aln2dLKdw) Topaz DeNoise approach on low ISO images.

Yes, although the method shown is dealing with high pass sharpening (a Creative sharpening technique), so one needs to adjust it if Capture sharpening is involved. For Capture sharpening one would use Denoise while trying to preserve high spatial frequency detail , and then apply deconvolution on the resulting image, and use that as an overlay of sorts.

But for macro shots, I assume we would usually have a setup that allows to shoot at low ISO for maximum image quality.

Cheers,
Bart
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: John Koerner on April 01, 2015, 07:35:38 am
On deconvolving noisy images, I gotta remember to try this (https://www.youtube.com/watch?v=p2aln2dLKdw) Topaz DeNoise approach on low ISO images.


Nice. Thanks for sharing.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Ancient Tiger on April 19, 2015, 07:26:51 am
Don't forget the Sigma 70mm macro.  It is now discontinued but you can still find it online new.

I have one and it is razor sharp. One of the reasons they do not make it anymore is that they cannot source some of the glass it uses anymore.  It is rather exclusive.

Bang for buck it is the best macro lens on the market for those who do not want 1:1 (it only does 1:2). Also the bokeh is reasonable for a macro lens. If it had HSM it would be perfect!
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: WannabeTilt on April 19, 2015, 08:46:37 am
Two legendary macro lenses I've see are the Voigtlander APO lanthar 125 mm / f2.5 and the Minolta APO Macro 200 mm / f4.
(snip)
But it would mean buying into a completely new system, unless you can find the Voigtlander lens for the Canon mount (don't know if they ever produced it with that mount)

Yes, Voigtländer did make the APO Lanthar 125 in EF mount - I have one. Foolishly - because I'm not a good enough photographer to make best use of it.

But this thread has been very informative, if a bit daunting. I must learn. Thanks to the OP and all who offered info and advice.

Nick
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Ghibby on April 21, 2015, 08:31:02 pm
Two options could work. For pure image quality not much is going to surpass the zeiss 135apo. Check out Lloyd Chambers coverage. Spectacular piece of glass. I use the zeiss 100 makro and it's wonderful but the 135 is a class above if you are happy with 1:4 magnification. 

A more unusual option is the canon 90mm ts-e lens. Very sharp plus allows full control of the focus plane with tilt movements. For studio work where you have time to set up properly it will be a lot easier than farting around with focus stacking techniques and get the shot done in one take with less intensive post work required. it could be a great option.

Ben
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Bart_van_der_Wolf on April 22, 2015, 05:40:50 am
A more unusual option is the canon 90mm ts-e lens. Very sharp plus allows full control of the focus plane with tilt movements. For studio work where you have time to set up properly it will be a lot easier than farting around with focus stacking techniques and get the shot done in one take with less intensive post work required. it could be a great option.

I agree, the TS/E 90mm is quite usable at short focus distances, and the tilt capability may be more useful than the ultimate sharpness that other lenses produce in an infinitesimally narrow DOF zone. Getting the focus plane positioned well, may be more productive than the alternative techniques. I recently did a comparison between my EF 100mm f/2.8L Macro IS USM and the TS-E 90mm f/2.8 with (very) close-up focusing, and there was only a minor reduction in quality (see attached animation, at roughly 1:3 magnification factor) that post-processing would allow to make even smaller.

Sharper lenses are usually nice to use, but with the shallow DOF of Macro photography there may also be other considerations that deserve attention.

Cheers,
Bart
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: AreBee on April 22, 2015, 07:45:15 am
Nancy,

Quote
That Focus Magic program looks to be worth a try.

Every time I use it I thank Bart for bringing it to my attention.

I cannot recommend it highly enough - it's astonishing how effective it is at sharpening...while leaving no trace of halos. Worth its cost several times over.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: PeterAit on April 22, 2015, 09:38:24 am
Olympus has a 50mm f/2 macro that has amazing optical performance. It's for M4/3 cameras, so it is 100mm equivalent focal length. Coupled with an E-M1 it's a great macro tool, although you are limited to 16 MP. As evidence, see the attached shot of a poppy - and this is a crop that contains only about 1/6 of the full frame!
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Ellis Vener on April 22, 2015, 10:57:47 am
This has been great and very useful conversation.

Smahn if you are looking into focus stacking also look into the CamRanger (http://www.camranger.com) and Stackshot (http://www.cognisys-inc.com) combination.

While I have been very happily using the CamRanger to drive my camera remotely from either my Mac or my iPad since it came out, including for focus stacking and exposure bracketing work, my focus stack work up to now  is not as precise as yours needs to be as it isn't  near-macro or true-macro-oriented. The StackShot rail and controller looks like it will add a great deal of precision to the process.

I use  Helicon Focus software (http://www.heliconsoft.com/heliconsoft-products/helicon-focus/) to process the stack

I also appreciate the mention of the Sigma 180mm Macro lens. Didn't know about before and am now very interested.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: NancyP on April 22, 2015, 11:32:28 am
For Canon APS-C users, I always recommend the EF-S 60mm f/2.8 as the perfect introduction to macro. Cheap and very very good. Its only flaw and advantage is the relatively short focal length and thus short working distance. Which reminds me - near-macro wide angle with shortish extension tube - time for me to try it. It is lovely to isolate one flower, but sometimes adding a little more background could be interesting. Getting lighting on the subject could be even more interesting... ;)
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Ellis Vener on April 22, 2015, 01:27:34 pm
I haven't used this lens but it looks interesting: http://www.amazon.com/Rokinon-100mm-Telephoto-Digital-Cameras/dp/B00VBHSH60/ref=sr_1_2?ie=UTF8&qid=1429650535&sr=8-2&keywords=rokinon+100mm
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: bjanes on April 22, 2015, 01:55:58 pm
This has been great and very useful conversation.

Smahn if you are looking into focus stacking also look into the CamRanger (http://www.camranger.com) and Stackshot (http://www.cognisys-inc.com) combination.

While I have been very happily using the CamRanger to drive my camera remotely from either my Mac or my iPad since it came out, including for focus stacking and exposure bracketing work, my focus stack work up to now  is not as precise as yours needs to be as it isn't  near-macro or true-macro-oriented. The StackShot rail and controller looks like it will add a great deal of precision to the process.

I use  Helicon Focus software (http://www.heliconsoft.com/heliconsoft-products/helicon-focus/) to process the stack

I also appreciate the mention of the Sigma 180mm Macro lens. Didn't know about before and am now very interested.

I am also a user of Camranger, but find its focus stacking facility somewhat limited. One can set the near focus precisely, but attaining focus at the far range is problematic. One can specify the step size (small, medium, or large) and the number of shots, but there is no good way to tell if one is taking too few or too any shots in the stack. One way to estimate this is to see how many steps in the focus adjust tab are necessary to reach the far focus point, but the step size there may not be equal to the step size in the focus stacking tab. Helicon Remote automatically determines the step size and number of shots according to the f/stop and other shooting parameters. Unfortunately, there is no iPad version of Helicon Remote, but they say they are working on it. I bought a small Nexus tablet to use with Helicon Remote, but find the Android interface of the program not to my liking.

What are your thoughts on these matters?

Bill
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Ellis Vener on April 22, 2015, 02:00:43 pm
I am also a user of Camranger, but find its focus stacking facility somewhat limited. One can set the near focus precisely, but attaining focus at the far range is problematic. One can specify the step size (small, medium, or large) and the number of shots, but there is no good way to tell if one is taking too few or too any shots in the stack. One way to estimate this is to see how many steps in the focus adjust tab are necessary to reach the far focus point, but the step size there may not be equal to the step size in the focus stacking tab. Helicon Remote automatically determines the step size and number of shots according to the f/stop and other shooting parameters. Unfortunately, there is no iPad version of Helicon Remote, but they say they are working on it. I bought a small Nexus tablet to use with Helicon Remote, but find the Android interface of the program not to my liking.

What are your thoughts on these matters?

Bill

What I do is inspect the last (the far frame) to see if I have gone far enough. If I haven't I simply shoot another sequence and the CamRanger focus stacking simply starts at the point it finished with the previous sequence.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: bjanes on April 22, 2015, 02:12:54 pm
What I do is inspect the last (the far frame) to see if I have gone far enough. If I haven't I simply shoot another sequence and the CamRanger focus stacking simply starts at the point it finished with the previous sequence.

Yes, that is what the manual suggests. I am relatively new to focus stacking and have experienced some difficulty estimating the step size and number of shots, and hopefully more experience with the setup will make it easier to get optimal results.

Bill
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Ellis Vener on April 22, 2015, 10:54:37 pm
hopefully more experience with the setup will make it easier to get optimal results.

It should, as by all appearances you are a pretty smart guy.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Bart_van_der_Wolf on April 23, 2015, 06:01:25 am
I am also a user of Camranger, but find its focus stacking facility somewhat limited. One can set the near focus precisely, but attaining focus at the far range is problematic. One can specify the step size (small, medium, or large) and the number of shots, but there is no good way to tell if one is taking too few or too any shots in the stack. One way to estimate this is to see how many steps in the focus adjust tab are necessary to reach the far focus point, but the step size there may not be equal to the step size in the focus stacking tab.

Hi Bill,

I don't know how the Camranger software calculates the number of steps, but it would need to know the right parameters for the lens because each lens is different. A small/medium/large step can be different depending on the (focal length of) the lens. You can use the procedure below to calculate the required number of shots.  I don't know if/how that interacts with the step size in the Camranger interface though.

Quote
Helicon Remote automatically determines the step size and number of shots according to the f/stop and other shooting parameters. Unfortunately, there is no iPad version of Helicon Remote, but they say they are working on it. I bought a small Nexus tablet to use with Helicon Remote, but find the Android interface of the program not to my liking.

There's always room for improvement, but in my experience the folks at Heliconsoft are open to suggestions. Not that they would implement anything thrown at them, but if it makes sense to them (given all considerations they have to balance) it might happen.

I also use a Nexus 7 with Helicon Remote. The only thing that one should figure out is the Correction factor to be used for the calculation of the number of steps that HR will use. The easiest way, rather than finding out by trial and error, is to calculate the DOF at the nearest focus position, and divide the total DOF depth to be covered by the single slice depth. The correct number of steps can then be created by tweaking the 'Correction factor' until they roughly result in the same number of shots.

To calculate the DOF for a single slice, I use the following formula that's most suited for Macro photography because it avoids focus distance:
Total DOF = (2 x C x N x (1 + M / P)) / (M^2 - (C^2 x N^2 / f^2))
where:
C = the Circle of Confusion, which I set to the sensel pitch in millimeters,
f = the focal length in millimeters,
N = the aperture value set on the lens, so not the effective aperture due to magnification, but the nominal one,
M = the magnification factor, as can be accurately measured from the size of the subject on the sensor divided by the actual size of the subject,
P = the pupil factor, the Exit pupil to Entrance pupil diameter ratio, or use 1.0 if unknown.
If all (C and f) units are expressed in e.g. metres instead of millimetres, then the result will also be in metres.

If the closest focus distance is used for the calculation, the farther distances will not have gaps in DOF range between the slices. Since the CoC is set equal to the sensel pitch, there will be no DOF gaps possible between slices, and the stacking software should be able to achieve optimum focus at each position through the stack. This achieves the highest quality at the pixel level, but for down-sampled image sizes one can relax the parameters with an amount equal to the down-sampling factor.

With extremely narrow apertures, diffraction will also reduce the resolution which will then also allow to relax the pixel quality requirements a bit.

Shooting with a focus rail that moves the camera+lens assembly, or the subject stage, leaves the magnification factor constant. That means that the same effective slice DOF is used for each shot, whereas a refocusing by lens will gradually increase the DOF as one focuses farther away. Therefore, in the latter case it's best to calculate the narrower DOF for the near focus distance.

Cheers,
Bart

P.S. EDIT: I've modified/rearranged the formula a bit to make it shorter and perhaps faster to calculate.
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: bjanes on April 23, 2015, 07:25:56 am
I don't know how the Camranger software calculates the number of steps, but it would need to know the right parameters for the lens because each lens is different. A small/medium/large step can be different depending on the (focal length of) the lens. You can use the procedure below to calculate the required number of shots.  I don't know if/how that interacts with the step size in the Camranger interface though.

Bart, thanks for the detailed reply. You mention Camranger, but did you mean Helicon Remote? Camranger does not calculate the number of steps, but rather relies on the user to input this datum.

To calculate the DOF for a single slice, I use the following formula that's most suited for Macro photography because it avoids focus distance:
Total DOF = (2 x C x f^2 x N x (M + P)) / ((f^2 x M^2 - C^2 x N^2) x P)
where:
C = the Circle of Confusion, which I set to the sensel pitch in millimeters,
f = the focal length in millimeters,
N = the aperture value set on the lens, so not the effective aperture due to magnification, but the nominal one,
M = the magnification factor, as can be accurately measured from the size of the subject on the sensor divided by the actual size of the subject,
P = the pupil factor, the Exit pupil to Entrance pupil diameter ratio, or use 1.0 if unknown.
If all (C and f) units are expressed in e.g. metres instead of millimeteres, then the result will also be in metres.

This approach is elegant, but I can foresee problems with my "macro" workflow, which is mainly closeup with a magnification of less than one. My MicroNikkor lenses are the G type which lack an aperture ring and the aperture is set electronically and with the effective aperture set by the in lens chip. Furthermore, these lenses exhibit focus breathing with shortening of the focal length as one focuses nearer.

Cheers,

Bill
Title: Re: Sharper Macro than Canon 5d2 and 100mm Macro?
Post by: Bart_van_der_Wolf on April 23, 2015, 08:44:42 am
Bart, thanks for the detailed reply. You mention Camranger, but did you mean Helicon Remote? Camranger does not calculate the number of steps, but rather relies on the user to input this datum.

I did indeed mean CamRanger, and I was indeed afraid it just uses the user input of step size and number of shots, instead of true steps. Helicon remote instead does calculate the actual number of required steps based on front and rear focus range limits, and then uses exactly that (tweaked by the correction factor).

Quote
This approach is elegant, but I can foresee problems with my "macro" workflow, which is mainly closeup with a magnification of less than one. My MicroNikkor lenses are the G type which lack an aperture ring and the aperture is set electronically and with the effective aperture set by the in lens chip.

If the camera doesn't exactly use the user's input for fixed Aperture value, then one can also convert between Nominal (at infinity focus) and Effective (at nearer focus) Aperture, before plugging the numbers into the earlier formula.

Nominal Aperture = Effective Aperture / Log((1 + M/P)^2) / Log(2)
or
Effective Aperture = Nominal Aperture x Log((1 + M/P)^2) / Log(2)

where:
M = Magnification factor
P = Pupil factor

The formula is supposed to be exact, regardless of magnification factors being larger or smaller than 1.0, with the possible small inaccuracy of conveniently rounded aperture number representations. A nominal f/5.6 for example would actually be more something like f/5.65685424949238 .

Quote
Furthermore, these lenses exhibit focus breathing with shortening of the focal length as one focuses nearer.

That would complicate focus stacking by electronic focusing, compared to using a rail.

I also have a small issue with the electronic focusing of my Canon EF macro lens, and that's to do with hysteresis caused by the focus drive direction. Switching the direction will shift focus, so one needs to account for that when determining the front and rear focus positions. When the camera returns to the start position, it may focus slighty in front or behind the earlier determined position, depending on the direction of approach. So it's wise to set the boundaries slightly wider than needed. Other than that, it works wonders, and saves time because I can do something else while the stack is being shot.

Cheers,
Bart