I am debating between the different 90mm lenses that are out there. There are a perture differences of 4.5, 5.6, 6.8, and 8.0. I know that there is a brightnes s difference but there is also a weight and cost difference. For landscape work , some in lower light, is it worth the extra size and expense to buy a faster le ns. Also is there a sharpness difference when shooting a f/16 or f/22? Thanks for any feedback from those of you out there using these lenses.
I use a Fujinon SW 90mm f/8 ; it is relatively small and light, certainly when compared to a 90mm f/5.6 lense, gives adequate movements for 4x5, doesn't need a centre filter (unlike certain older lenses), and gives excellent results - 16x20 enlargements from Velvia transparencies taken with this lense are very sharp. It would certainly be interesting to compare it to a Nikkor, Schneider or Rodenstock. I mainly use apertures between f/22 and f/45 ; there is certainly a difference in depth of field, but I can't see diffraction effects appearing at f/45 (then again, I'm not an expert on this). In low light, it can however be difficult to focus at f/8, especially at the edges of the groundglass because of the fresnel. A 4x loupe is a real help in such circumstances.
My choice was the Super-Angulon 90 mm f5,6 (non XL) mainly because I wanted to u se it for interiors also. It is a very good lens too, but the heaviest of all my lens bag! Performan ces are at the top. No center filter needed if movements are moderate. It is the lens I use the most fo r interiors. A very good focal for landscape also. I have not used a f8 but I think it is fine for exteri ors and weight and price are in favor of this choice.
Co,aring fast to slow and Rodenstock to Schneider is easy. Just ask for the curves.
Yeah, but not everyone understands those damn charts (well, I certainly don't) but I've just been through this and the only way to do it is to try all the options if possible. I had a fujinon f8 90mm, but it was quite old and not as sharp as my newer schneider lenses. So I went to my local dealer and did a lens comparison b/w my fujinon, a Rodenstock 4.5 90mm grandagon and a schneider superangulon 5.6 90mm XL. Obvoius coverage differences apart, (all the test shots were done at the same time, same subject) there was a huge difference b/w each lens and unfortunately for my bank balance, the super angolon XL was the winner by miles. It was the sharpest at all movement ranges and as far as focussing in low light, because of the huge image circle the edges were quite easy to see when I recently shot some low-light interiors with it - but be warned, its a big bit of glass!!! Not to mention the filter siz
For landscape work, with small movements, I would choose a slower lens unless all of your work is done close to the car. The f/6.8 Grandagon is a nice lens when stopped down to f/22 or so. The f/8 Nikkor is the only slower lens that uses an 8 element formula like the faster lenses. This gives it a bit more coverage than the other f/8 and f/6.8 lenses. The Nikkor is also quite small and light, and has a good reputation among field photographers as being quite crisp at shooting apertures.
"Yeah, but not everyone understands those damn charts (well, I certainly don't) "
then ask us to mail you the nice detailed tech sheet Rodenstock publishes on reading MTF, distortion and color curves. It's free to anyone in the U.S.
My 90mm f8 Nikkor is my favorite lens. Light, sharp, good contrast, good coverage and a great bargain used. I use it indoors and out. It was a bit difficult indoors at f8, but since adding a fresnel things are better. I chose this over the Nikkor f5.6 because its is lighter (I hike alot), cost less and tests show that it is actually sharper. Although, my guess is that the differences are not readily detectable with the naked eye.
Another thing the "charts" will show and users will see is that the fast lenses don't produce equally brighter images at the edges of the field. Wide open, these lenses show much more than cos^4 falloff. So although they are 1-2 stops brighter in the center of the field, they are often only 1/2 to at best 1 stop brighter in the corners, where invariably, the subject of critical focus has positioned itself.
"Another thing the "charts" will show and users will see is that the fast lenses don't produce equally brighter images at the edges of the field. Wide open, these lenses show much more than cos^4 falloff. So although they are 1-2 stops brighter in the center of the field, they are often only 1/2 to at best 1 stop brighter in the corners, "
But the corners are different. For example 114.8mm is the 1/2 diagonal of the 90mm 6.8 but 121.5 is the same for the 4.5. At 114mm the 90 4.5 has less fall off then the 6.8.
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