"Soft" Nikon 300mm

[Stewart Skelt]

Thanks Steve, that's a very kind offer.

I'm near Canberra but family in Melbourne so get down your way several times a year. If I can't resolve the issue I may PM you.

[ChuckP]

Using f90 and f128 may be the problem. Too much diffraction? Definitely try some exposures at f22-32 to see how they look.

[SteveR]

No worries, we regularly travel between Geelong and the Eastern Suburbs of Melb, so if it comes to it, I'm sure we could work something out.

[TheFlyingCamera]

Just a thought - I assume you're using some kind of "top hat" lensboard extension to mount this lens and use it on your Wista. This is creating an extension above and beyond the limits of the camera platform, which would magnify any vibrations you would get through the tripod, or with wind. Also, given the depth of the "top hat", is it possible you've not fully tightened the retaining ring? One more thing to look into - often lenses like that came with a shim to go between the lens element set and the shutter body (usually on the rear element, but not always). Check and see if A: your lens has a shim, and B: if it does not, try to find out if that lens model shipped with a shim. Often the shims are significantly less than 1mm in thickness.

If you can't solve your problems, I'd consider getting a Fuji 300T f8. Not only is it faster (nominally) but it's also a true telephoto, so it requires less than 300mm of bellows to focus to infinity. Downside is limited movements. If you have to switch, you could probably get an even-up trade from your Nikon to a Fuji 300T.

[Ian Grant]

Manufactures sometimes use shims when matching up pairs of cells so it's not necessarily dependent on the model/batch rather just their QC getting the best from a particular paired combination of cells. This is also why some lenses have serial numbers on both front & rear cells,

But Scott's observation of the extension etc mirrors my experiences that it's a difficult lens to use on 5x4, that extension amplifies any shake,

Ian

[Nicholas Lindan]

I generally expose on f/90 or f/128. Will try some apertures in the middle of the range to see if they are better.

A rule of thumb is that the optimum aperture is equal to the focal length / 6 for a 'normal' lens.

Like most rules of thumb there are probably more exceptions than adherents.

As an example:

format - F.L. - optimum f-stop

35mm - 50mm - f8
6x6 - 80mm - f11
4x5 - 150mm - f22
8x10 - 300mm - f45

The better the lens, the wider the optimum aperture. A good APO lens will have an optimum that is 1 to 1 1/2 stops wider.

Using a 300mm on a 4x5 means you are only using the center of the lens' coverage, the Nikkor is close to an APO, and so f22/f32 will yield the best results.

Using the 300mm (4x5) at f128 is about like using a 50mm (35mm) at f22/f32 - soft results should be expected.

[Stewart Skelt]

TheFlyingCamera: Yes, it's a "top hat", but the "crown" (ie the part that the lens attaches to) screws off, making access easy. When using this lens (and a big Fuji 210 that also uses an extension) on my Horseman, I always use the forward mounting point for the tripod shoe, to balance the camera and minimise shake.

ChuckP and Nicholas: Thanks very much for that advice. My "rule of thumb" - obviously wrong - was to use an aperture one or two back from the smallest. I'll try using f22 and f32. It will be a while before I get the opportunity but when I have I will bump this thread and report results.

[Stewart Skelt]

Bumping the thread as promised to report results. Yes, images taken at f22 are much, much sharper. So thanks for all the advice, and I'm keeping the lens!

[Tom Stanworth]

phew, I was going to chime in there that f90 and f128 is going to cause serious diffraction induced softness!

Even my cheapo 300 f9 Geronar is tack sharp at f22-32. I love a bargain!

[ic-racer]

Ian and Peter: I never use the lens wide open. I generally expose on f/90 or f/128.

Woa, you just answered you question.