Yes, I agree, the 120mm f/4 Macro is a great lens, probably one of the best for the system. why don't you walk us through your shooting technique from the ground up.
f32 can't be helping. Mirror up is essential.
f32 can't be helping.
With your 9 micron sensor and the 120mm you can get decent results at f16 or even f22 with a bit of sharpening. If you need more DOF I suggest that you use Focus stacking
Has anybody done much in the way of macro work with an MF and do they have some results online to compare and contrast?
Has anybody done much in the way of macro work with an MF and do they have some results online to compare and contrast? I've been messing around all day trying to get some decent images from the Mamiya/ZD with 120mm macro lens and have not achieved anything that I am happy with. In fact this is the best I managed and it's just too soft to my mind. I'm trying to work out if it's me or the camera or whether I'm expecting too much.
Erik K. Do you best to control yourself. I'm not going anywhere else with this discussion other than posting these images.
Erik
I knew you couldn't resist! ;D
but wished you would have!
btw - the 2 dollar bill in my image is at 45 degree angle to the lens axis - but you saw that right? That's also why I have the ruler there - so I can quantitatively see the DOF. My image is as 3D as needed.
My images show clearly diffraction losses with the 120, and they aren't as bad as you might guess.
Well I can certainly see a few areas of where I was going wrong and heartfelt thanks to the all who have suggested where matters might be improved. The question of aperture had never occurred to me as in my innocence I was thinking that the smaller the aperture the better the DOF without even realising that this created another set of problems with a digital sensor.
Justinr,
Looks better definitely but I'm still wondering if you can't get even sharper. I posted the 2 dollar bill examples to show what sharpness is possible with the 120mm lens, and how aperture settings will affect it. I often will use a small flash for macro work positioned close to the subject as the flash duration is quite short with the small flash units - much shorter than with a studio type strobe. With a flash speed of 1/5000 or faster you don't have to worry much about vibration or movement. If you can eliminate the vibration and movement, and have the aperture and focus set well, then what's left to check is the lens itself. But DOF will be very small when you are focusing up that close, perhaps only a centimeter.
I wouldn't expect either of those to cause you problems.
Do you get sharper images with the camera & back with other lenses?
Why don't you try tethered shooting to ensure precise manual focus?
I think you're onto something with the 120 lens as the 80mm shot did look better. I'm not sure your 120 is up to spec. However you might want to take a series of shots with the 120 while focus bracketing just to rule out any possible focusing issues. Just find the place on the lens you think is correctly focused, back up a bit and take about 10 shots moving the focus in tiny steps. If you don't get any shots as sharp as with the 80 then you'll know for sure.But, shoot at f8 or f11 this time. I think even f16 is too much.
Just to give an idea of scale, I have a problem with lens sharpness rather than DOF it seems.
I think you're onto something with the 120 lens as the 80mm shot did look better. I'm not sure your 120 is up to spec. However you might want to take a series of shots with the 120 while focus bracketing just to rule out any possible focusing issues. Just find the place on the lens you think is correctly focused, back up a bit and take about 10 shots moving the focus in tiny steps. If you don't get any shots as sharp as with the 80 then you'll know for sure.
I'm pretty sure at f/16 with your back, you'll still get usably sharp images and you'll need it since the DOF will be very thin otherwise.
In the comparison you posted of the pentax and lichen, it seems that neither subject is entirely within the DOF as both have areas of sharpness and softness. I'd say your DOF is only a few mm deep only. This isn't enough to catch everything.
Have you tried backing away from your subject yet? A farther camera to subject distance will increase the focus DOF (depth of field). In the example's I posted, the one with the rollei 150mm the DOF isn't sufficient to cover the thickness of the medallion, but in the mamiya 120 samples you can see several inches of DOF - therefore backing away is one way to get your subject to be all included in DOF. It means you have to crop down your file significantly, however you may end up with a more usable image.
I think that I am getting somewhere now.
This was taken with the Mamiya 120mm lens at f16 and and about an inch further away. The big difference is though that it is a stack of 12 shots using Combine XP. I'm still not 100% happy but it's looking a lot better.
If you are willing to focus stack, then it's better to use a little bigger aperture - perhaps f/11 would be a good compromise between number of frames and sharpness for your setup.
Definitely you've made some improvements, but still I wonder if this is as sharp as you can get it?
So what we are saying is that if using focus stacking then we might as well rely on the software to provide DoF whilst trying to provide the sharpest material for it to work with?
Keep also in mind that if you use extension, it makes the real aperture smaller. So f/16 at 1:1 is usually f/32.
Lest we create more confusion (Circles of? ???) here, this needs some clarification. For purposes of discussing diffraction, f/16 is f/16, regardless of focus distance or magnification. At 1:1 magnification, the amount of light coming through a given lens opening, say f/16, is spread over 4 times the area it would be covering compared to infinity focus. Thus, any given spot on your sensor is receiving 1/4 the illumination intensity, hence the 2stop loss. The key word here is intensity (remember, e=i x t). This has nothing whatsoever to do with how much diffraction you have at that aperture. So, when your lens is set to f/16 and your image magnification is 1:1, your illumination intensity or exposure is the equivalent of f/32(2-stops loss) but your diffraction remains what it would be at f/16.
That's not correct.
Diffraction is based on effective aperture, not marked aperture (unless your camera system makes adjustments to account for bellows-loss for the displayed aperture).
This effect becomes quite obvious when dealing with very high magnification imaging. At 18:1 magnification diffraction on an 80mp back is meaningful starting at a lens marking of f/2.8 :).
Think of it from the perspective of the sensor: Here is the same sized physical opening, as seen with more and less extension:
(http://www.doug-peterson.com/wordpress/wp-content/uploads/2009/08/Mamiya-AutoBellows-4-aperture-small-151x180.jpg)(http://www.doug-peterson.com/wordpress/wp-content/uploads/2009/08/Mamiya-AutoBellows-4-aperture-large-151x180.jpg)
You can read more about this in my article on Extreme Macro Photography (http://www.doug-peterson.com/macro-extreme-technicals/).
2. You use a motion table to move the subject through the plane of focus, is this to avoid having to touch or disturb the camera [...]
[...]or do you feel that there is some optical advantage over moving the plane of focus through the subject as I do by adjusting the lens?
Eric
I have attached the middle slice of the stack taken with the 120mm. I didn't have too much time yesterday to do much more than this image.
That's not correct.
Diffraction is based on effective aperture, not marked aperture (unless your camera system makes adjustments to account for bellows-loss for the displayed aperture).
This effect becomes quite obvious when dealing with very high magnification imaging. At 18:1 magnification diffraction on an 80mp back is meaningful starting at a lens marking of f/2.8 :).
Think of it from the perspective of the sensor: Here is the same sized physical opening, as seen with more and less extension:
(http://www.doug-peterson.com/wordpress/wp-content/uploads/2009/08/Mamiya-AutoBellows-4-aperture-small-151x180.jpg)(http://www.doug-peterson.com/wordpress/wp-content/uploads/2009/08/Mamiya-AutoBellows-4-aperture-large-151x180.jpg)
You can read more about this in my article on Extreme Macro Photography (http://www.doug-peterson.com/macro-extreme-technicals/).
Hi,
Thanks for chiming in. Checked out your article and liked it.
I have still not found out the issue OP has, but it seems he made progress and that is a good thing.
Best regards
Erik
I am indeed and it's all due to the kind help I am receiving here.
I have posted the latest attempt at the lichen below, the discs are approx 1mm in diameter.
This was taken with a stationary camera and fixed lens at f8 and under exposed by half a stop or so. The subject was moved through the focal plane using a jury rigged motion table of such crudity that I daren't mention its construction here. :) Anyway, 21 slices were taken at 0.8mm apart approx and this was the result of the stacking.
Edit. I've also attached an original slice.
I have posted the latest attempt at the lichen below, the discs are approx 1mm in diameter.
Edit. I've also attached an original slice.
1. Lighting. I note that you shoot in the dark to avoid shutter 'shake' but do you feel that extraneous ambient light or slight over exposure will reduce the clarity of the image? I slightly underexposed the bike shots to test this (although it's in no way a true comparison) for the brighter areas of the lichen shots appeared the least sharp.
2. You use a motion table to move the subject through the plane of focus, is this to avoid having to touch or disturb the camera or do you feel that there is some optical advantage over moving the plane of focus through the subject as I do by adjusting the lens?
Hopefully this is not too off-point for the OP, but Doug, I'd like to congratulate you on your very systematic presentation and discussion of "Extreme" macro work. Your illustrations are immensely informative.
I'd be tempted to open a dialogue with you off-line if you like, so we don't distract from the OP's direction. I use a Hassy-555ELD with Zeiss-135+bellows, and the Sinar P2 with SK Makro-Symmar-HM-80, Roden Macro-Sironar-120, SK Makro-Symmar-HM-180 (a superb lens in all aspects...), and Roden Macro-Sironar-N-300 (which requires an unbelievable amount of supplemental light at full extension!).
Your inclusion of the Velmex moving-table is brilliant, and one I'll pursue myself. Also, your discussion of diffraction+extension is a basic steep learning curve for the effective use of bellows. I certainly agree with your summary of stitching errors using Helicon Focus, and I'm impressed by your "several hundred images" successfully stitched! I've found I can work Helicon either closer-to-farther or the reverse, with about the same results. You're quite right about maintaining the continuity of sequencing!
And, last but not least, I appreciate your addition of the non-moving shutter, something I have not attempted with my Aptus-65, but will explore, now that I've seen your results.
All in all, a very informative expose on "extreme" macro creativity! Thank you.
One more image and crop of the same bunch of flowers but here one of the flower had gotten old and dropped out of the vase.
My apologies for dropping off the radar and not getting back to you all but have been busy elsewhere over the last couple of days.
Justin.
What is your shooting distance, measured from sensor plane?
I think you should back up and just take some normal shots, and evaluate the plane of focus, even if it's not where you actually focused. I mean, it shouldn't be that hard to get sharp detail.
EricW, the dollar shots you posted show f/20 being sharper than f/16. Are you seeing the same thing? Is there any reason why it doesn't just keep going downhill after f/16? Or maybe I'm seeing things wrong...
ps. T-1000
I agree with you and have been suggesting to back up and try to get one good frame with the whole subject within DOF.
Erik K - have a look at Justin's picture of his set up, his comment about the lichen disk's being approx 1 mm across, and also the picture with the ruler. You'll get an approx idea of magnification. Not that it really matters, anyhow, since magnification differences at this level is mostly going to impact the size of the DOF and not how sharp the sharp part of the DOF is.
In every shot there should be one slice that's sharp. I'd suggest working on getting that part sharp before worrying about stacking or other stuff. Also Justin you might be having focus issues. I'm still wondering about the 120. Another thing to look at is your lighting. Small flash units work great for macro work since they can be placed quite close to the subject and are relatively large in scale to tiny subjects. The most important part is the flash duration is quite fast compared to studio strobes. This really helps mitigate camera or other vibration.
I use a pocket wizard on the camera and one on the flash to get the flash close to the subject and off camera for more interesting lighting.
On reflection of my own tests, I feel that what is lost to diffraction can be regained in part, but fine low contrast structures will be lost, I rechecked the images you have posted, and checked out the f/8 and f/16 images. I took to the freedom to cut and paste from your postings. The f/8 image shows a paper structure while the f/16 image shows very little paper structure.
Don't forget that while my $2 bill shots were taken with the mamiya and 120mm lens, the Aptus ii 12 back used has 5.2um sensor pitch, but Justin's back has larger. I have noted diffraction starts to be noticeable between f/8 and f/11 on the 80mp backs, however its not that noticeable and some lose can be 'mitigated' through software.
My lily pictures are clearly affected by diffraction but still usable - they look quite fine a normal print sizes even though I present a 100% pixel peeping crop.