Fuji GW690III lens test - my results

[david b]

Brief test of Fuji GW690III 90mm lens

 

After reading advice on Photo.net, I bought a mint used Fuji

GW690III, that�s the one with the 90mm f/3.5 lens. Rather than

irritate everyone with the �I�ve just bought this camera, what do all

the rest of you think of the lens?� type of question, I�ve tested it

myself.

 

I put it on a big Gitzo tripod, and shot a sheet of newspaper taped

to a wall, 2m away. Lighting was natural daylight. I made exposures

at apertures in �full� stops, i.e. f/32, f/22, f/16 etc down to f/4,

and then f/3.5. Film was Velvia.

 

I think there is very slight, only just perceptible, vignetting at

f/4 and f/3.5, but not at f5.6 or wider. The overall contrast and

sharpness are excellent, with even the smallest news print appearing

very sharp.

 

I cannot see any fall off in quality, even at the edges or corners at

tiny apertures. Is this the experience of other GW690 users? I was

prepared to accept that the lens might be softer at f/32 and f/22

than perhaps in the mid range.

 

Any comments on this?

[kevin_sperl]

WhenI furst purchased this camera I tended to adhere to the "rule" of not using a smaller aperture then is needed for any given image. Since then I have started to shoot a lot at f/32 and f/22. This allows me the greatest DOF since I want to include some foreground to make for interesting images. I now tend towards the suggestion I beleive I first read by John Shaw. Stop down and then hyperfocal focus as if you are opened up one stop. That is, for example, stop to f/32 and then hyperfocal focus to f/22. I get very sharp images this way. Of course, Always on a tripd.

[andrew_schank]

F22 isn't a very small aperture with 6X9. Remember, the view camera guys often shoot at settings like f64. In fact, use anything larger than f11 and its hard to get consistant edge to edge shapness because of film flatness problems in 6X9 roll films. I did a similar test with my 6X6 camera on a resolution chart, and what was really interesting was taking several frames at the same exactly the same lens openings. There was an obvious difference in the detail resolved in the different frames taken at exactly the same apertures, especially at the wider openings. F16 seemed to give the most consistantly good images with my Rolleis, so that is what I use whenever I need the sharpest images possible, like in landscapes. I started using the faster films in my roll film cameras, and think the small trade off in grain is offset by being able to use the optimum lens openings with faster shutter speeds if needed.

[sal_santamaura]

I have a GW670III (same lens) and have also tested for resolution at all apertures, including half stops. Note that these cameras have straight across film paths, so flatness is nowhere close to being the issue it is with most Rolleis. Multiple frames exposed at the same aperture gave negatives indistinguishable from one other. Also, newsprint at 2 meters is not very demanding. My test used an Edmund Scientific resolution chart at 11 feet 2 inches.

 

There is a definite deterioration of performance with smaller apertures. Results were quite good at f/5.6, better at f/8 and optimum at f/11. Things got progressively worse from there down. Evaluation of the TMX (developed in Xtol) negatives was done with a 15x magnifier.

 

Having said all this, it is important to note that, with 8x10 prints made on graded fiber based paper, viewed at about 12 inches, it is virtually impossible to pick the negative made at f/11 from one exposed at f/22. I can just barely see a difference with the f/32 negatives. Should you make larger prints, and if your enlarging system is up to the task, shooting aperture might be a consideration. In most situations, I wouldn't hesitate to use f/16 or even f/22 if necessary for depth of field. Subject matter would dictate whether I'd be willing to go as small as f/32.

[don_gillette]

Well Dave: I just got to use my second hand gw690 recently acquired and I was very pleased to say the least, I had been using an old Kodak Medalist till now, but that fuji lens is awesome. I could resolve things that the many others couldn't. I used f22 at 1/15 and 1/30 on a tripod. Under my microscope I couldn't detect edge falloff that would amount to much. As for the shutter , I used to repair cameras and know that a shutter in need of work usually acts up in cold temps. It was 31dgs F.not a lick of problem and the exposures were right on. Frame spacing was excellent. This spring I plan to do some color work and will test everything with high mag, and densitometer. Just maybe I will save for a Gsw..Don