Mike: Here's the third vote (fourth?) for checking that the ground glass is where it is supposed to be. Stick a line of objects on a fence, focus on one you'll recognize on the negative, and shoot one sheet with the lens wide open. If the glass is out of register, you'll know it. Are the objects you are comparing for sharpness the same absolute size in the negatives?
This is a process of eliminating variables to find the culprit.
Check the negative itself, not the print. Is it sharp? (Using transparencies as suggested is also an option). If the negative is sharp, then the fault lies in the enlarging process, not the camera nor camera lens. Problems can be ... well, you probably know what can cause an unsharp enlargement. Post again, if you don't.
Thanks everyone for the quick and thoughtful responses. And thanks also to Bob for the great customer service. My camera is a new Toyo field camera. I have done no modifications on it. I find myself shooting anywhere from f16 to f32 usually. I went and looked at my trasperancies as suggested (thanks) to eliminate the enlarger. The change from 4x5 to medium fmt is the same in the slides. It seems to occur in both the 90mm and the 180mm equally. It does seem unlikely that they would both be off and by the same amount (appx). So, it would seem more likely that my gg to holder position is off. The suggestion of lining up objects then shooting one with the lens open seems like a good idea. Any others? And if that is the case, how do I fix it?
Thanks again
A couple of thoughts...
The Toyo is designed to have its fresnel in front of the groundglass (iow insi de the camera); disagreements about proper fresnel position aside, the absence o f a fresnel lens or perhaps it being put on the back of the groundglass could ca use a problem. If the camera's brand-new, that's most likely not the problem.
Considering the groundglass itself, it's pretty dark, which can make focusing difficult with the wide lens. Even so, you _should_ be able to focus accurately enough.
Be sure you're using enough magnification in a loupe, but not too much; around 4x-5x is best. Too little won't give enough magnification to clearly see focus, while too much will magnify the groundglass graininess and fresnel rings so muc h that it'll also make focusing difficult. Worst is the common cheap 8x Agfa (an d other) plastic loupes. If you don't have a decent loupe, just try viewing the groundglass through a reversed 35mm to 50mm lens off a 35mm camera; that makes a great high-quality loupe.
Mike, I would add the following points....
1. If your using a new Toyo Field and Toyo holders, I would not look there for the problem. Toyo puts every camera thruogh a laser test to assure gg / film alignment. If it is off, MAM usa will correct this and check it if you beleive its a problem, assuming you are in the USA. If it's happening with both lense, it obviously is not the lenses...the chances of two bad new lenses is nill. You are shooting the LF lenses at the desired f stops, so thats not an issue.
2. Maybe your expectations are too high? I shoot with the Toyo AII and also the Mamiya7. In general MF lenses using modern glass will clearly produce sharper chromes of EQUAL size. However, the limitation of resolution to film is limited more so by the film, not the lenses. So although MF lenses will deliver sharper chromes, and higher contrast images to film, the difference is not significant enough to make up the 2x larger 4x5 film. MF lenses would have to deliver 2x the resolution "to film" to overcome the 4x5 2x size advantage, this is impossible. The limitations of any camera system is limited to the total system, as described in a formula in the back for the Fuji handbook ...bottom line, even the best glass in the world can not improve on-film resolution by more than 25% , i.e. better than your LF lenses. This is also evidenced by C Perez tests results of LF and MF glass.
3. I know this may sound obvious, but it was not addressed above. A fair comparison would be to look at each image using an adjustable loupe. Inspect each chrome at the same final size. This would equate to a 4x loupe setting on the 4x5 chrome and a 8x loupe setting on the MF chrome. Now you are looking apples to apples at the final print size with the same loupe. If doing this experiment, the MF looks sharper, its time to have your gg / film alignment checked. If you were looking at both images at the same magnification, than nothing is wrong! My M7 chromes blow away any LF chromes I shoot, even with my Schneider SS XL's.
I think the best LF glass is inferior to the best MF glass. LF lens designers probably felt there was no need to match the sharpness since the film size more than overcame the small difference in sharpness. But after reading a few threads on this board, it seems this is changing as the new digital LF lenses seem to have MF sharpness that can be used on LF film.. I think the image circles are big enough for 4x5... maybe someone can comment on these lenses for Mike. If not, you can re check the threads for the posts I am referring to. Hope this is helpful!
I think the physics of the situation works against LF with respect to smaller focal lengths, in general. Consider what a lens does: It bends finite points of light and brings them into "focus" with some degree of accuracy, the higher the accuracy the sharper the image. It stands to reason, then, that the greater the distance between the refractive surfaces and the film plane the more lens aberation will be magnified. Sure, there are abundant examples of fuzzy short lenses and sharp long lenses. It's just more difficult to make sharp long lenses.
I recall reading, some time ago, when those little Kokak disc cameras were popular, that the lenses in them resolved 80 lpm. They were made of plastic and were very short.
The lenses used in aerial recon, by the military, also resolve 80 lpm. and they are long....but extremely expensive.
In the end it is market forces that determine how sharp a lens is. How sharp do you have to have it? How much are you willing to pay?
I think it has to be the back, I have a TK45 and a hasselblad, when I compare the negatives the ones from the TK45 are much sharper than those from the hassie, even though the ones from the hassie have more contrast, the reason I think they "appear" sharper. So beleive me, the 4x5 should be sharper, even with cheap lenses, I sometiems use a Nikkor 210 w, and although the contrast is horrible the negs from this lens come out sharp as ever....good luck.
Since we haven't nailed it yet, look for the obvious.
1. Using a tripod with the 4x5? Is it heavy enough to stabilize the camera?
2. Any chance of camera motion?
3. Any chance of subject motion? (You didn't say what the subject was.)
4. Using a cable release?
4. Do the lenses project a sharp image? Try this at night: open the shutter, and focus the image of a bright light source (street light, moon, porch light, whatever)on a matt sheet of paper--can you get the image in focus?
Do you have an experienced LF friend close by who could look at your equipment & technique?
While MF lenses are better than LF, no way should any LF negative have unacceptable sharpness when things are aligned & used right. My simple 4x5 portraits just bowl me over compared to MF & 35mm. In fact, I think LF has generally been underappreciated in portraiture. Suberb tonality and detail. Sorry you're not seeing it yet.
If, by chance, you're in the SF Bay area, & you can't figure it out, I offer to meet you to help see what's going on.
Thanks Charlie for your kind offer. I really do wish I could take you up on it, I could use some help in large format technique. However, I am in Virginia. I have never used, seen one used or even known anyone who had a large format camera until I bought mine. But over the past months I have read most of the recommended books on the subject and surfed the net nightly in my studies. Through trial and much error I am getting better. As far as the lens issue goes, my tripod, etc is very stable. I ran a couple of tests and looked at the results. I also went back over some of my prints looking for clues. The first test I did that was suggested here to me was photographing one object in a row of objects with the lens wide open. I did this with both my Rodenstock and Nikon. I put a few cases of Corona (left over from my wedding) in a row on my deck rail and the one I focused on was the one that came out sharpest with both lenses. I used these cases because I would not only be able to see the edges but also the writing on the boxes for comparison. (I could also drink one as it was about 96 outside) I used tmax in a readyload and my regular Toyo holder for this. Both looked the same under a loupe. The thing i did notice though, is that the Rodenstock is a sharper lens. But even more noticeably it has better contrast and much more "local" contrast. This makes the Nikon lens look a bit soft in comparison. I then went back and looked at my prints and saw that show up in those too. My next test was suggested to me by Jeff at Badger Graphics. He suggested that one reason my images are not as sharp as I want them might be because I am not stopping down enough. I took a water ski I have with crisp, bold writing on it and stood it up agains a brick wall. I then took some pictures with my Nikon each at a different stop to f45. I then examined them under a loupe. Under a loupe and to a lesser extent with my naked eye I can see the images getting sharper to f22, then about the same at f32 then falling off a bit at f45. Chances are I do need to stop down more than I thought. But really the lens is still not as sharp as I would like it and more importantly it does not have as much contrast as I would like to seperate the details. I did however find some portraits I did with the Rodenstock that are fantastic, both in sharpness and contrast. So obviously my technique in certain situations is more than suspect and needs improvement. So, I will keep working at it until I have more sucesses than failures- then I will work harder. Because as most of you I have never enjoyed photography as much as when I am using my large format camera. And with such a great instrument it would be a shame for me not to use it to its potential.
Mike,
Your tests are interesting, but let me suggest another interpretation. Starting with the waterski test (and assuming you were trying to focus on the ski): this may actually suggest that there is a problem w/ your GG alignment. Increasing sharpness as you stop down is likely an indication that the ski was not actually in the plane of focus (since stopping down increases depth of field but doesn't change focus on the exact plane of focus. Note, however that stopping down could result in some increase in sharpness on the plane of focus because it also can eliminate some lens aberrations.)
The beer case test may not be sensitive enough to pick up the GG misalignment. (The case you focused on could have been the closest to the plane of focus although not on it.) You might try it again by lining up the bottles, closely spaced, and see whether the one you focus on is in the best focus on the negative. (I'm assuming you haven't drunk them all by now.) Good luck.
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