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Author Topic: Not worth it ?  (Read 28500 times)

tho_mas

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Re: Not worth it ?
« Reply #140 on: November 25, 2013, 06:35:46 pm »

What sharpening are you using?
Personally I do not apply sharpening at the RAW stage. I first apply (multi-step) sharpening when the image is resized to the desired size...
But concerning your RAWs I've viewed them in C1 with the standard sharpening I use to preview my P45 files.

Quote
It is interesting that your images are sharper than mine, as the Contax lenses are said to be very similar to the Zeiss lenses on Hasselblad V
well, actually we would have to do side-by-side comparisions to be sure... but I am talking about my overall impression of your RAWs based on my experience with my P45 files. But the Hassy vs. Contax thing aside the more intressting point is the use of high res digital LF lenses (Digitar & Rodenstock HR)... these are extremly sharp lenses but I still do not see that kind of color artefatcs ... According to your theory I should see more color artefacts and more fake detail when using sharper lenses on the same DB. But I do not ... I only see a more sharp/more detailed image ... for whatever reason.
And while we're at it... I also shoot a P21+ (9 microns!)... and the very same lenses also do not show more color artefacts when shooting this back. The files are just "brutally" sharp (either way if I use the Contax or the digital LF lenses). Of course the P21+ is more prone to show pattern Moiré, but, again, this is a different story ...
So in my - personal !! - experience something simply doesn't add up ...



« Last Edit: November 25, 2013, 06:37:40 pm by tho_mas »
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jjj

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Re: Not worth it ?
« Reply #141 on: November 25, 2013, 06:42:03 pm »

No need for a sharpening race, just do each as best they can be done. Simply see how well artefacts can be removed and how well they sharpen. The only real comparison that can be made is after PP is finished as best as can be done. Doing both the same is not really relevant as you didn't use same camera settings.


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Fine_Art

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Re: Not worth it ?
« Reply #142 on: November 25, 2013, 06:56:36 pm »

The color fringes may or may not be pronounced (or suppressed/leveled out) in the raw software. May also have to do with the "calibration" of the DB. I've looked through some of your captures (raws). Although your captures seem to be somewhat soft they show quite a lot of color artefacts. I do shoot almost the same back (P45 non-plus) on Contax and while my captures (raws) are typically sharper/more detailed they also show much less color artefacts. I also shoot the very same back on a tech cam with very sharp lenses and while the captures are sure even more sharp/more detailed than shot with Contax lenses (at least at the edges...) the back still doesn't show that much color artefacts.
I don't want to say my back does not produce color artefacts ... it does. But overall much less... and much less pronounced.
Moiré, of course, is another story...
So your findings may very well apply to your kit... but not necessarily to MFD in general...??


Color artifact are a completely different issue. They are about how well the lens is apochromatic. Many lenses approximate focusing the 3 primaries to the same spot. Many fail. The lens in question probably has an element out of alignment or the coatings are failing.

Attached is a screenshot at 100% with all sharpening off. very fine lines, pixel level lines, can still be seen with mild stairstepping. That is all you can ask of a lens in terms of resolution. Give me clean separation at the pixel level. If I turn on sharpening all that happens is contrast is cranked.
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ErikKaffehr

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Re: Not worth it ?
« Reply #143 on: November 25, 2013, 08:35:20 pm »

Hi,

Thanks for your observations. I don't have any decent explanation. I know Lightroom produces more color artifacts than C1

Best regards
Erik


And while we're at it... I also shoot a P21+ (9 microns!)... and the very same lenses also do not show more color artefacts when shooting this back. The files are just "brutally" sharp (either way if I use the Contax or the digital LF lenses). Of course the P21+ is more prone to show pattern Moiré, but, again, this is a different story ...
So in my - personal !! - experience something simply doesn't add up ...




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Erik Kaffehr
 

ErikKaffehr

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Re: Not worth it ?
« Reply #144 on: November 25, 2013, 08:40:31 pm »

Hi,

The issue below is not CA.



Best regards
Erik

Color artifact are a completely different issue. They are about how well the lens is apochromatic. Many lenses approximate focusing the 3 primaries to the same spot. Many fail. The lens in question probably has an element out of alignment or the coatings are failing.

Attached is a screenshot at 100% with all sharpening off. very fine lines, pixel level lines, can still be seen with mild stairstepping. That is all you can ask of a lens in terms of resolution. Give me clean separation at the pixel level. If I turn on sharpening all that happens is contrast is cranked.

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Erik Kaffehr
 

Fine_Art

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Re: Not worth it ?
« Reply #145 on: November 25, 2013, 11:42:16 pm »

Hi,

The issue below is not CA.



Best regards
Erik


I think the technical terms are spherochromatism and transverse chromatic aberration if it mostly shows up away from the center. Either way, your pictures deserve a try with a different sample lens.
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ErikKaffehr

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Re: Not worth it ?
« Reply #146 on: November 26, 2013, 01:32:06 am »

Hi,

Anyway, I am most thankful for your comments. Much appreciated.

A guess is that this may also do with subject. The things that show these colour artefacts is normally small detail at close to pixel size. Sail boat rigging is very typical, pine needles against white wall. Unfortunately also waves on water. I see it often in test shots but seldom in normal photography.

The reason that my images are softer than yours at the raw level is interesting, it may depend on slight front focusing.


Best regards
Erik


Personally I do not apply sharpening at the RAW stage. I first apply (multi-step) sharpening when the image is resized to the desired size...
But concerning your RAWs I've viewed them in C1 with the standard sharpening I use to preview my P45 files.
well, actually we would have to do side-by-side comparisions to be sure... but I am talking about my overall impression of your RAWs based on my experience with my P45 files. But the Hassy vs. Contax thing aside the more intressting point is the use of high res digital LF lenses (Digitar & Rodenstock HR)... these are extremly sharp lenses but I still do not see that kind of color artefatcs ... According to your theory I should see more color artefacts and more fake detail when using sharper lenses on the same DB. But I do not ... I only see a more sharp/more detailed image ... for whatever reason.
And while we're at it... I also shoot a P21+ (9 microns!)... and the very same lenses also do not show more color artefacts when shooting this back. The files are just "brutally" sharp (either way if I use the Contax or the digital LF lenses). Of course the P21+ is more prone to show pattern Moiré, but, again, this is a different story ...
So in my - personal !! - experience something simply doesn't add up ...




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AreBee

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Re: Not worth it ?
« Reply #147 on: November 26, 2013, 02:14:08 am »

Fine_Art,

Quote
The lens in question probably has an element out of alignment or the coatings are failing.

Coatings fail?
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EricWHiss

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Re: Not worth it ?
« Reply #148 on: November 26, 2013, 02:21:16 am »

The color fringes may or may not be pronounced (or suppressed/leveled out) in the raw software. May also have to do with the "calibration" of the DB. I've looked through some of your captures (raws). Although your captures seem to be somewhat soft they show quite a lot of color artefacts. I do shoot almost the same back (P45 non-plus) on Contax and while my captures (raws) are typically sharper/more detailed they also show much less color artefacts. I also shoot the very same back on a tech cam with very sharp lenses and while the captures are sure even more sharp/more detailed than shot with Contax lenses (at least at the edges...) the back still doesn't show that much color artefacts.
I don't want to say my back does not produce color artefacts ... it does. But overall much less... and much less pronounced.
Moiré, of course, is another story...
So your findings may very well apply to your kit... but not necessarily to MFD in general...??

I'm with tho_mas here Erik:  I've been somewhat baffled by your sample images actually since its not what I see.  Also in your sample image with the bill - the purple fringing around the black test chart marks leads me to believe either you haven't focused properly (axial CA) or there's another issue going on with your set up.  I've shot bills with all kinds of digital backs from DMR to AFi-ii 12 and multishot backs.



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ErikKaffehr

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Re: Not worth it ?
« Reply #149 on: November 26, 2013, 02:44:02 am »

Hi,

Yes, I can confirm that the Sonnar 150/4 has axial chromatic aberration. I don't think that is the issue, however. I will try to reshoot the image with focus bracketing, as I plan some other test shoots this week.

Best regards
Erik


I'm with tho_mas here Erik:  I've been somewhat baffled by your sample images actually since its not what I see.  Also in your sample image with the bill - the purple fringing around the black test chart marks leads me to believe either you haven't focused properly (axial CA) or there's another issue going on with your set up.  I've shot bills with all kinds of digital backs from DMR to AFi-ii 12 and multishot backs.




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Erik Kaffehr
 

synn

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Re: Not worth it ?
« Reply #150 on: November 26, 2013, 02:51:01 am »

I might be the odd man out here, but I fail to see how any of this analysis paralysis would actually answer the question "Whether MF is worth it or not". People who opt for MF as a tool, as I plan to do shortly, do it for a variety of reasons, none of which involves looking at charts and graphs and 100% pixels for hours.

Sorry if I offended anyone, but a tool is a tool. It's about finding the one that fits ones requirements best.
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ErikKaffehr

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Re: Not worth it ?
« Reply #151 on: November 26, 2013, 04:56:21 am »

Hi,

The pixels are forming the image...

Best regards
Erik


I might be the odd man out here, but I fail to see how any of this analysis paralysis would actually answer the question "Whether MF is worth it or not". People who opt for MF as a tool, as I plan to do shortly, do it for a variety of reasons, none of which involves looking at charts and graphs and 100% pixels for hours.

Sorry if I offended anyone, but a tool is a tool. It's about finding the one that fits ones requirements best.
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Fine_Art

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Re: Not worth it ?
« Reply #152 on: November 26, 2013, 10:17:39 am »

Fine_Art,

Coatings fail?

From cleaning (abrasion), peeling, pollution (or any chemical reaction; sea spray?), fungus eating it, sometimes it has holes to begin with where it did not stick at manufacture.

High end multicoatings are a large part of the cost of lenses. We do well to inspect carefully at purchase to make sure they are intact.
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Fine_Art

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Re: Not worth it ?
« Reply #153 on: November 26, 2013, 10:30:43 am »

I might be the odd man out here, but I fail to see how any of this analysis paralysis would actually answer the question "Whether MF is worth it or not". People who opt for MF as a tool, as I plan to do shortly, do it for a variety of reasons, none of which involves looking at charts and graphs and 100% pixels for hours.

Sorry if I offended anyone, but a tool is a tool. It's about finding the one that fits ones requirements best.

IMO the advantages of MF are 2:

Anytime you have to get a massive amount of data in 1 shot. Otherwise stitch.

Larger lenses allow the curves in the lens to be smoother relative to the limit of grinding technology. Theoretically you could design in more precise rendering style.

The latest lens manufacturing tech is using a jet of liquid to shape the rotating lens at the molecular level. The new crops of ultra lenses are probably from this machine. Even aspherics. I think it makes the old limits of putting together systems of spherical ground lenses history.
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ErikKaffehr

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Re: Not worth it ?
« Reply #154 on: November 26, 2013, 03:40:06 pm »

Hi,

I would agree on point one, if you talk about high resolution backs, like IQ 160 and up. Not really P25 class. I agree that P45+ has better detail than 24 MP digital.

Regarding lens technology, I do disagree. Small lenses are generally regarded to be easier to design for high performance. Exotic technologies make it first to cell phone cameras, check the enclosed screen dumps from an article by Carl Zeiss. And please not the MTF diagram goes to 80 lp/mm instead of the usual 40 lp/mm.

There are a couple of glasses in today's glass catalogs allowing for moulded aspherics. Almost any lens you can buy today has a couple of aspherics.

Best regards
Erik





IMO the advantages of MF are 2:

Anytime you have to get a massive amount of data in 1 shot. Otherwise stitch.

Larger lenses allow the curves in the lens to be smoother relative to the limit of grinding technology. Theoretically you could design in more precise rendering style.

The latest lens manufacturing tech is using a jet of liquid to shape the rotating lens at the molecular level. The new crops of ultra lenses are probably from this machine. Even aspherics. I think it makes the old limits of putting together systems of spherical ground lenses history.
« Last Edit: November 26, 2013, 04:07:02 pm by ErikKaffehr »
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EricWHiss

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Re: Not worth it ?
« Reply #155 on: November 27, 2013, 02:17:50 am »

Yes, I can confirm that the Sonnar 150/4 has axial chromatic aberration. I don't think that is the issue, however. I will try to reshoot the image with focus bracketing, as I plan some other test shoots this week.

Erik, the Axial CA shows in the just out of focus areas - so if you see it in your test chart with the lens set to a small aperture, my best guess is you have not focused well. There are other causes of purple fringing but the P45+ has great control of blooming so I'm not thinking that is the cause of it on your test images.  More likely Axial CA.   You could actually use this as a guide for focusing. Goes from purple to green and when you are in focus none.
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ErikKaffehr

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Re: Not worth it ?
« Reply #156 on: November 27, 2013, 02:41:05 am »

Hi,

I know axial chromatic aberration well, and I can observe it during focusing. But I don't think that is causing the issue shown, because the colors are different. A bit also because I used the slanted edges for MTF measurement and the MTF on those images was "darned good". My guess is that LR4 landscape sharpening preset was used but I don't know.

You see that MTF at f/4 is close to MTF at f/5.6, and it drops at f/8. Note also that the f/5.6 image shows paper structure on the dollar bill. The image was shot at around 3.5 m.

Very clearly, I will spend some more time looking into this. Doing som focus bracketing, to begin with.

Best regards
Erik

Erik, the Axial CA shows in the just out of focus areas - so if you see it in your test chart with the lens set to a small aperture, my best guess is you have not focused well. There are other causes of purple fringing but the P45+ has great control of blooming so I'm not thinking that is the cause of it on your test images.  More likely Axial CA.   You could actually use this as a guide for focusing. Goes from purple to green and when you are in focus none.
« Last Edit: November 27, 2013, 02:43:11 am by ErikKaffehr »
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