can't get sharp photos with an LF camera

[Bernice Loui]

Some areas are fuzzy focus, some areas are sorta focus, some areas are kinda sharpish. This points to the limitations and realities of a flat bed scanner and film flatness. Or, film flatness in holder to grind glass/fresnel to film in film holder distance issues.

Regarding the film flatness in film holder issue, clip from the Sinar propaganda regarding film flatness and film holders. Also why so much tooting about BIGer sheets of film gain more film flatness problems.


Challenges with film flatness, camera precision/accuracy relative to ground glass/fresnel distance and tolerances to film in film holder is magnified once large aperture lenses are used. Stopping down can hide various camera problems.

What are the image "sharpness" expectations from images made?

This was posted some time ago in regards to this obsession of "sharpness". The 5x7 Ektachrome was made decades ago using a Goerz 14" f9 APO artar (@f22), 5x7 Sinar C, Sinar shutter. Note the difference between 4990 flat bed scanner -vs- Leica M420 microscope at 260x magnification.

https://www.largeformatphotography.i...420-microscope

Reality is, none of this makes as much difference as believed or perceived, if a projection enlargement print is limited to never more than 4x, obsessive stuff like Uber sharp and all that is simply not that relevant in the finished print. What is FAR more important becomes image content, it's expressive qualities and IMO, tonality along with all those non "sharpness" focused aspects of the print.

This previous discussion applies here:
https://www.largeformatphotography.i...bigger-picture


Bernice

[xkaes]

If you run the simple ruler test with the lens (open or stopped down) -- mentioned days ago -- it doesn't matter if your eyesight is bad or your scanner is messing up. Something -- one spot -- on the negative will be as sharp as that lens can get -- even if your ground glass is misaligned.

If no plane (ruler distance mark) in the negative is sharp enough, then the problem in the lens.

That's the place to start first -- determine if the patient is alive or dead before you start operating.

[Havoc]

Some areas are fuzzy focus, some areas are sorta focus, some areas are kinda sharpish. This points to the limitations and realities of a flat bed scanner and film flatness. Or, film flatness in holder to grind glass/fresnel to film in film holder distance issues.
.....
Challenges with film flatness, camera precision/accuracy relative to ground glass/fresnel distance and tolerances to film in film holder is magnified once large aperture lenses are used. Stopping down can hide various camera problems.

What are the image "sharpness" expectations from images made?

Could be I'm running into the limits of the scanner. But I don't think so. I'll get the light table out end of April (not at home the next week and weekends). As for large aperture... when used at f/22 think this is in the region where those various problems should be hidden.

Well, I expect it to be better than this. I expect to be able to read 10cm high letters on a billboard 5 meters out. Letters like that are worse than the flatbed scan of the stop board in your example. And that stop sign is a big lot smaller than the letters I would like to be able to read. Like the text on the 4 banners on the grave of the 4x5 photo in Amiens cathedral. I expect it to be as least as good as a 1950's Kodachrome projected 1.5mx1.5m by an ordinary projector on a common family screen.

If you run the simple ruler test with the lens (open or stopped down) -- mentioned days ago -- it doesn't matter if your eyesight is bad or your scanner is messing up. Something -- one spot -- on the negative will be as sharp as that lens can get -- even if your ground glass is misaligned.

If no plane (ruler distance mark) in the negative is sharp enough, then the problem in the lens.

That's the place to start first -- determine if the patient is alive or dead before you start operating.

It is on the list for next week. Won't be able to develop until end of April. But it will be done. I'll even do it with several lenses to see if that gives any variation.

[xkaes]

I'll even do it with several lenses to see if that gives any variation.

It's always good to have something to compare it to. I hope it's not your lens -- but that would make it simple, and avoid a lot of other work. It happened to me once. I sold the lens, got another one, and the problem was solved. As a result, the first thing I do when I buy a lens -- new or used -- it test it against another lens. There are duds out there -- and not just used gear, but it's especially important to check used lenses. Let us know how it goes.

[Bill Poole]

To me the most problematic of these scans is the one of the church altar--not sure what's going on there, with some areas very soft. (I could not see an aperture noted for that one, which might be an issue.) The two outdoor images seem within limits of what I would expect from a V700 scan, especially if they haven't been sharpened, which all digital output needs in my experience. For what it is worth, I never scan at greater than 3600 DPI on the V700, and even that is not supposed to be a whole lot better than 2000 dpi according to what I have read from others. I very much like the 6x9 image, probably because I am more familiar with T-max and like its look. It's hard to isolate variables in apples-to-oranges tests. (Diffrent films, lenses, etc.) Good luck nailing down your issues. Hope this helps--ignore if not.

[RichardRitter]

Find someone who has a working darkroom or send the negatives to a service that dose darkroom printing.
Have contact prints made and have one or two enlargements made.
Compare to the scams and digital prints.

[cptrios]

To me, the crane image doesn't look too bad for what it is, and the church altar has some really obvious camera shake. Actually, it looks almost as if the focus was nudged forward/backward during exposure, since it gets progressively worse as you move out from the center.

Edit: I just noticed that you shot that on CMS 20. That must have been a very long exposure. Lots of things could have happened during that time!

[Bernice Loui]

Don't expect uber resolution results from a flat bed scanner. The 4990 is used to share images via data only. Seems 2400 dpi (nee ~10 microns per pix) is about the reasonable limit for these Epson flat bed scanners. A good optical microscope objective with green light (~500nm) will do about 0.2_ish micron. In both cases, film/image flatness, overall system stability makes ALL the difference.


IMO, non of this is that important if the enlargement is not more than 4x. Sheet film can offer much improved overall tonality and other aspects aside from "sharpness" over smaller film formats.


Bernice

[Joseph Kashi]

FWIW - I've found when scanning 5x7 Ilford Delta 100 that I got significantly sharper scans when I stopped scanning using the flat bed or open film holders and instead started doing wet scans with the inexpensive Epson wet scan film holder, which works up to 5x7 film. I'm using an Epson V850.

The actual stepper motor maximum inter-line resolution of the V850 is about 2900 dpi, so using a 3200 pi setting is about the maximum dpi that could make any practical difference. I usually use 2400 dpi - from my perspective, I cannot perceive a meaningful difference between a 2400 dpi wet scan and a 3200 dpi dry scan.

[r_a_feldman]

To me, the crane image doesn't look too bad for what it is, and the church altar has some really obvious camera shake. Actually, it looks almost as if the focus was nudged forward/backward during exposure, since it gets progressively worse as you move out from the center.

Edit: I just noticed that you shot that on CMS 20. That must have been a very long exposure. Lots of things could have happened during that time!

I see two issues with the altar image:

1. There was camera motion. The blown-out highlights in the upper left show diagonal motion, like a back-slash \.
2. The floor is sharp — even out from the altar — and the metal railings are sharp, indicating that the plane of focus was too close to the camera and/or not parallel to the vertical.