Remember that any given sample of a lens might not be representative of all samples.
Remember that any given sample of a lens might not be representative of all samples.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
Chris,
There are two flavors of the 75mm Apo Rodagon, one for 1:1, the other for 1:4. You must use an efficient lens hood with both as coating is not as efficient as with modern macro lenses. In my tests of both with a USAF high resolution target I was able to get over 200 lpm with the sony a7r iv in 16 shot pixel shift, quite a bit less with 4 shots.
I still have a Howtek also but for most types of high resolution digitizing I am finding it more convient to use a digital camera. So to get as long life as I can from the drum scanner I use it rarely and only when highest possible quality is needed.
Sandy
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I will look for the tests but am pretty sure that once I made up my mind as to the difference they were trashed. I keep stuff like this on my desktop for a while but when it seems to have no more use it goes to the trash.
In spite of the slightly superior results with the a7r iv I like to use the GFX 50R and constructed a horizontal stand to digitize very large format film with the Fuji. Will try to post a picture of the set-up later today. It required just a bit of work cutting and gluing.
Sandy
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Even if the A7xxxxx produces better scans, if you're more likely to use and enjoy the Fuji then you should factor that in. Just depends on where your priorities are. The 50R will make 50mp scans minus the crop you have to apply (or plus the stitching you do). There isn't anything inherently wrong with that number. There is always something 'better'. But as I always say if your maximum print size does not require Platos ideal scan, just do what works! The fact that you can zoom into the molecular level of a scan won't matter in an 8x10 print.
Personally I would skip the exotic Rodagon lens because I've seen in tests that its' really not better than the Sigma 70mm ART. For the Fuji their 120 macro is likely top notch, and autofocus is great when doing a lot of scans.
When copying via digi camera, I wonder if there's any advantage to wet mounting?
The Sigma 70mm Art is indeed a very good lens, and also very low flare. However, in my own tests with high resolution targets I have found both of my Apo Rodagons give higher resolution. I also prefer to use manual focus with film digitizing since once you lock it in there is no need to do it again. I find the auto focus of the Sigma to be a bit less reliable than manual focus, about two times in ten I can dial it in closer with manual focus.
And what is exotic about an Apo Rodagon? Although they sold for a lot of money when new both versions of the 75mm Apo Rodagons that I own cost about 1/2 what I paid for th 70 mm Sigma.
Sandy
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A wet mount scan has some slight advantage in that it slightly increases micro-contrast of the file, and probably reduces touch up time. But in most cases I find that the final output size needs to be about 8X for this to make much difference. So for medium format with 16X20 final output, probably makes a difference. For 4X5 with 16X20 final output, maybe not.
Sandy
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Exotic may be the wrong word but they do require a bellows focusing rig and generally more 'fussing'. In the test I saw the 75 performed very well in it's 1:1 sweet spot but fell off at other magnifications. So if you're not stitching full time and shooting any 120 or sheet film it pays to get a lens that is more versatile, at least IMHO. I'm sure the ultimate results are not THAT different so really it's whatever you're willing to put up with.
A fixed magnification rig does not require using a macro bellows unit. I use rigid extension tubes with integral mounting feet. The tube(s) are bolted to a long Arca plate along with the camera. This is simpler, lighter, and sturdier than any bellows unit. I do use my PB-4 to figure out extensions for given magnifications.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
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