lots of Q's: #1what f-stop is the sharpest

[Nate Klueter]

#1
I wasn't aware that f-stop affected the sharpness of a lens till yesterday when i started reading lens reviews on dpreview.com. Is this the same for film cameras? I have been trying to find information about what f-stops would be the sharpest for my current cameras. I have quite a long list of lenses but I'm mainly concerned about the ones I use most. Is there any general rule like the middle range f-stop is usually the sharpest? It seems like dpreview's lens reviews usually find f4-8 the best.

Nikkor 28mm f/3.5 (3.5, 4, 5.6, 8, 11, 16, 22)

Nikkor 55mm f/1.2 (1.2, 2, 2.8, 4, 5.6, 8, 11, 16)

Olympus C-5050z 7.1-23mm f/1.8-2.6 and as low as f/8-10 would really like to get an idea of which f-stops are best for this since I've started using it a lot.

#2
I also have a tamron 28-200mm asph. for canon eos mount but I've always prefered prime lenses as I felt zooms weren't as sharp. So do you think the nikkor's are better? *edit I found this listed on photodo.com and it got a 2.7 score so it probably is much worse.

#3
I want to get a lens hood for my 55mm nikkor. I found Nikon | HB-34 Bayonet Lens Hood | 4126 | B&H Photo Video. Will this be the correct field of view since its for a 55mm zoom or not?

K, that's all for now. Thanks for any help.

 

[Torus34]

The sharpness 'sweet spot' of a lens is independent of whether it is used for film or digital photography. You can save yourself lots of time [and use it to work on taking better pictures, instead] by simply assuming your lenses are at their sharpest 2-3 stops down from fully open.

While it's nice to know this information, it usually doesn't mean a hoot when actually taking a picture. There, the decision of motion control vs. depth of field takes the palm.

 

[dinodan]

RE: Question #2. I'm a bit confused by the question (Canon vs. Nikon). IN GENERAL, prime lenses are sharper than zooms. Having said that, there are some really good zoom lenses available, and there's a lot to be said for the convenience of having one lens that covers multiple focal lengths. Depending upon many variables, the difference in the final result (i.e. photo) between a zoom and prime lens might be negligible or non-existent.


RE: Question #3. No, the HB-34 is definitely NOT right for your 55 lens. I'm assuming that what you have is a manual focus AI or AIS 55mm. This takes a screw-in shade, not a bayonet shade. Attachment size (diameter) is 52mm, which is very common. There are a lot of shades available in that size that should work. I don't know what the Nikon part number is. Any moderately-sized 52mm shade should work with the 55 without vignetting.

 

[Nate Klueter]

So that hood has the interlocking notches and no threads?

 

[dinodan]

So that hood has the interlocking notches and no threads?

Correct. The shade for your lens will not be a "petal" type, as these depend upon the bayonet mounting to end up in the proper orientation on the lens. Threaded shades are the conventional round type.