With my Fuji I switch on the centre AF points and centre that group inside the reflected lens filter ring. I don’t see any issues with mis-alignment but this is only with 24MP. When you get it Vlad’s Test Target it will easily show up any such issues when focus peaking on the Siemens Stars.
Yes, that’s the principle. @Graham will know how best to use the 105 Sigma though. Maybe AF works well enough?
With the Sigma, I focus using the Velmex Unislide (focusing rail) after getting close with the focussing ring in manual focus, I have used the remote focusing via the computer with IEDT Remote but it’s a bit laggy and in steps. AF works well but I feel happier with manual and Velmex. I choose a focus point on the film between the centre and edge and depending on the subject. I use either the highest focus magnification or the next one down. The magnification factors vary with cameras.
The tricky part is: if you’re shooting at f8 that’s the aperture you’re focusing at with it’s greater depth-of-feild than fully open, so it slowly goes in and out of focus. You can focus wide open then stop down but it’s a pain (you have to adjust the exposure back and forth each time and there’s risk of movement). It’s a shame Sony doesn’t have something similar to the inverse of “depth-of field-preview" like an old SLR camera, to focus accurately.
Mainly for mounted slides where I need to go a bit closer to exclude the mount I add a 10mm extension ring so you’re not at the limit of focus which the lens doesn’t like.
Left is the Camera scan. Comparing a same size crop reveals that your tech is not too bad.
Focusing is kind of difficult indeed, but once you know how to do it and with enlarged live view (or screen of your MILC) you’ll be able to put the inspected part of the image in perfect focus.
As @Mark_Segal describes, you can optimize your setup. And do a thing that I’ve learnt in a different context: Adjust things against their play or creep. E.g. manual lenses tend to creep downwards, so you want to adjust focus going upward. Apply that principle to all the places that use screws and you should get a more stable setup. You can also check whether the geared head you use needs to be reoriented in order for gravity to tighten screws rather than loosening them.
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You might also try ditching the geared head and align using the adjustable feet on your film holder, or better still a larger home made levelling base around the same size as your copy stand base. I’m very wary about extending the camera away from the pillar of your copystand, it is almost bound to increase the risk of vibration even though you are doing everything you can to avoid it. See Vlad’s piece on vibration here (even though he is using a geared head!):
…or indeed @digitizer’s own setup (at least one of them):
Thanks Harry. I’m not quite convinced the holding mechanisms are causing this at this point (maybe over time they will drift) but near term while im fiddling i don’t think its a prime suspect.
I think my two prime suspects at this point are
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Lens
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alignment to the film plane
The reason I say that….I just got the Sigma 105 Art. From my initial tests, literally just setting it up quickly trying to align the best I can, and taking a shot…the softness is gone. Literally in 10 min I was able to get a pretty damn crisp shot that rivals the sharpness of the Nortisu with NO additional sharpening on my end. The grain itself doesn’t look blurry. I spent 4 hours with the Sony 90mm and NEVER got this level of sharpness. My Vlad tests are coming in either this week or early next, so I’ll be able to do a test to test more objectively.
I tried to match the size, colors, exactly like @Digitizer did on his sample above to be able to do at least the same type of comparison like he said. To me its easy to tell which is sharper. But maybe I’m biased? I was clearly wrong above.
The part I am struggling with now is the alignment…I really don’t want to spend $180 for a mirror with a hole in it.
One other question that I am not 100% sure about…
If I set the macro lens to its minimum focus distance (using MF), and then use the rails to adjust it to focus…at the 1:1 macro it is slightly too close so I don’t get the exterior part of the film (e.g. the sprockets), is this intended? Do I need to back it off ever so slightly? Will I lose sharpness and I need to keep it at the lenses MFD?
It sounds as if you have made great progress with your new lens. There is no real downside in terms of sharpness to backing off the lens from 1:1 to get some rebate, I would certainly do that myself. Too much rebate and I suppose you run the risk of some flare. I quite understand why @Mark_Segal uses those tools for alignment but I think you might find that you can refine your technique with a single plain mirror used carefully to achieve the results that you want.
Thanks. I’ll do tests with the Vlad test targets when I get it with both lenses and double check, but the new lens looks promising.
Then at that point it will be stabilizing the rig, granted I haven’t quite figured out how to orient my setup within 3d space.
This is a mirror setup I did (brought in an additional light so I could focus on the aperture blades, which I was able to get dead center.
Here is a scan with the Art105 if they are bored.
A few items come to mind
- Orient the geared head in such a way that you can use the controls you need most
- Orient things so that gravity tends to tighten the connection rather than to loosen them.
- The vertical column is the item that works like a string, although you manage well according to the new screen capture. You can restrict the column’s movement by adding some strut(s) or brace(s) that extend from the baseboard to close to where the superclamp is attached. Doing this requires a bracket that fits your column.
Looks like a perfect alignment.
All things considered, I get the impression that you are ready to scan. One thing can still spoil some of the fun: Films tend to be not properly flat due to age or how they were stored. This means that a center focus can be perfect and other parts appear out of focus. Some of the necessary depth of field can be obtained by closing the aperture…but not too much in order to avoid softness due to diffraction. What kind of DoF you can expect can e.g. be calculated with THIS.
Acutance seems higher in the lower LH corner than in the center of the image. This seems to be in the original take due to where you focused or due to compromises built into the lens you took the photo with. Here’s a manual conversion done in PhotoLab and its Fuji Acros 100 film simulation.
Note: Due to full perspective correction, the buildings seem to lean. Our brain does such things and for less irritation, the correction should be reduced and/or the image rotated slightly CCW.
BTW: Congratulations for your dust control!
We haven’t considered one item yet: luminance noise or grain makes a photo look sharper.
I’ve verified this with DxO PhotoLab which has excellent noise reduction on a pair of virtual copies, one of which also got some grain added back. And guess what, the grainy image looked sharper and more authentic to me. Our brains seem to have better edge detection than whatever the apps provide…yet.
@Digitizer How would that apply for me in this case? I think in my case the issue really comes down to the sharpness of the lens. Obviously I can tweak the shots like you did, but if the lens fixes what I am seeing…I don’t see what I was seeing not partially the lens? Wouldn’t adjusting the Sigma 105A the same as the Sony 90mm shot just make the Sigma 105A even better?
So I got my Vlad’s test target in and did the test between the two lenses.
Sigma 105A: https://drive.google.com/file/d/1mZzamcpcwD4Wb5OjiqKuDCxvcVfzoIAj/view?usp=drive_link
Sigma 105A 2nd shot: https://drive.google.com/file/d/1I53RF3VHUr96bU8m9Fq8vIEB-qZ4vKaO/view?usp=sharing
Sony 90mm: https://drive.google.com/file/d/12dhHNa71bobuoufKVmKCMM99-4biT3j7/view?usp=sharing
Sony 90mm (2nd shot): https://drive.google.com/file/d/1P5055q2MB7ErYphougOnBiJc4S75iqf5/view?usp=sharing
Had the Sigma 105A already on the camera, took a picture. Reset focus and manually focused again took another shot (10s timer).
Put the Sony 90mm macro on it, centered and calibrated again with the mirror and did the same thing. Focused manually, took 10s timer shot. Refocused, did another 10s timer shot.
To me on the edges it is night and day. Maybe if I futzed around with the 90mm macro I could get it slightly cleaner, but to me, my results are consistent with the reviews. The the 90mm macro is not near as sharp as the Sigma 105A. The Sony might have other measurable that make it better, but for my purpose of scanning, the Sigma 105A is just flat out better.
I am just going to sell the Sony 90mm..but before I do…and while I have these two lenses…any particular tests anyone want me to do with them?
When I look at the comparison you posted above, I see a slight difference in how grain/noise shows in the two images. The left part noise looks rougher, on the right, noise looks finer and more even. Seen from a certain distance, the image at left looks sharper although it is about the same as the other when pixel peeping edges.
Do the following: take an image, create a virtual copy and add some grain. Take the nose off the screen and look if the two images appear equally sharp. Look, don’t “scan” for details, “feel” the image and see where it takes you.
Deeper shadows can also raise the perceived sharpness.
Thanks for uploading your files, it’s very interesting to be able to compare them. Just looking at them quickly side by side in Lightroom at 100% I’d agree with your ‘night and day’ conclusion, to me the Sony 90mm shows itself to be a poor lens for 35mm film copying on the strength of these results. However is it just the Sony 90mm lens in general, or maybe is it just this sample or even some other factor?
Firstly please note that when looking at them I have turned them all round through 180 degrees so that the text ‘Vlad’s Test Target’ is the correct way up and it makes it easier to refer to the LT, CT, RT, LM, CU, CD, RM, LB, CB & RB labels for each of the targets.
Looking at the Sony 90mm the RT, RM & RB results are much worse than either the centre or left hand sets of targets, there is poor definition and what appears to be a certain amount of smearing (if that’s the right term). This could be alignment or it could be the lens itself but it’s not good. It’s the same on both frames but looking at the centre 3074 looks to be slightly sharper than 3075.
I don’t see that at all with the Sigma 105 images, They seem excellent but again to me the first image, 3071, is very slightly sharper than 3072. However, looking at 3071 to me the corner targets are slightly sharper than the centre two (CU & CD) so this is most likely a depth of focus/film flatness problem. Have you tried different apertures? You are using f4 for both lenses, maybe f5.6 or even f8 might be better. It would be easy to test of course.
Yeah, Im not quite sure what happened there, I guess the gyro thinks it’s upside down slightly?
I’m not familiar with what “LT, CT, RT, LM, CU, CD, RM, LB, CB & RB” mean.
Yeah, i took two different manually focused shots, to give a little variation in “focusing”. When I’m focusing it’s hardly any movement, like I’m borderline even touching the focusing ring on either lens just visually trying to get it sharp.
Vlads test targets don’t give any feedback in regards to “grain” so I’m just guessing if it’s in optimal focus.
With the film picture of the building with the Signa 105A I can focus on the grain, the image on the back of the camera almost goes to a slightly splotchy image. With the Sony 90mm, I can focus and get it to focus on the grain, but it’s ever so slightly “off”, and not near as distinct. I’ve manually focus hunted for 30 min trying to focus it and still can’t get it perfect. I am just chalking that up to the lens not being as sharp.
I have not tried different apertures. I can do that. I just looked at the reviews online of where the lens tests sites showed the Sigma Art105 was the sharpest which was f/4, from the best I can tell that is the same as for the Sony 90mm.
Not sure what I can do with the film holder. I feel it’s about as flat as it’s going to get with the Valoi holder and advanced.
This has been nice to read through. Just keep testing to see what you experience and want to opt for but I would say you have hit a great spot. You are doing more than most people would and seeing the benefits. Chasing the dragon of perfection only leads to diminishing returns at some point.
One thing to note about sharpest apertures on lenses:
sometimes the needs of DoF, corner sharpness, and vignetting outweigh using the sharpest aperture.
This all then also depends on how flat field the lens is, how much it vignettes, and how flat the film is (older mounted slides often being a challenge). Obviosly flatness defines a LOT of how effective all this is and is an advantage many other types of scanning often (not always) show off as their biggest strength: edge to edge, uniform sharpness.
My Valoi holder does everything perfectly fine. Only way to get flatter costs more in either time or money using devices that mechanically flatten, like Filmomat Autocarrier ($$$), a Lobster Holder ($, slower), holders from enlargers (manually very slow), glass sandwhich with masks, and many other options. Only the best images deserve the extra effort towards perfection IMHO unless you are running a scanning lab or shoot tons of film for paying clients.
Because I have mostly been doing slides the 70 Art and 105 Art are both very sharp at f4 but I tend to use 5.6-8 range for more margin of error and improved far corner sharpness. On roll film in the valoi or pressed flat, I use 4-5.6 range.
I still have never done a direct head to head with my macro lens fleet, all bought for different projects and different times in my life. Sigma 70 Art, Sigma 105 Art, Sigma 150 APO, EF 100 L, and ScannerNikkor 100 2.8 (ish). I really need to. Need to sell the EF 100 because its clearly the weakest by a long way. But work always keeps me from more deeply exploring.
Cheers y’all
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Have you tried focusing using the rail rather than on the lens, so moving the camera and lens together? Definitely worth trying half stops up to around f8, there is usually a difference to be seen even with a half stop change.
Each of the targets is labelled so Left Top, Centre Top, Right Top, Centre Up, Centre Down, Left Middle, Right Middle, Left Bottom, Centre Bottom, Right Bottom.
I’ve tested the Sigma and found that vignetting occurs at f2.8 and f4. f5.6 and f8 are pretty much identical in sharpness with no vignetting. So to get greater depth of field I use f8.
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