Tilt/Shift with Wide Angle

[Doremus Scudder]

OK thanks, this is all very informative - love it. I didn't realize the f/45 diffraction issue. I'd like to see an example of the diffraction degradation - ... It's a pity to have f/45 on the lens and be excluding this aperture from my repertoire. Maybe diffraction can be put to good use artistically. Maybe I need to learn how to emphasize it rather than let it be a subtle component.

Alan

Alan,

Don't let me scare you away from using a smaller aperture when necessary. However, be aware that an "optimum" aperture exists for just about every situation that balances depth-of-field and degradation due to diffraction. Many simply ignore diffraction, since its effects are small and really only become apparent at very small apertures together with a high degree of enlargement. I use f/45 occasionally when I need it; I just plan to keep the print size small enough that the diffraction doesn't bother me.

For more info see the article on the LF home page here: http://www.largeformatphotography.info/fstop.html . There are lots of other great articles there as well, which I highly recommend.

Best,

Doremus

[alanmcd]

A bit of tilt, even with very short lenses, will enable you to focus on both a very near and a very far object and still use a relatively large aperture. Whether that's something you want or need to do often is another question, but there are times when a bit of tilt will definitely help focus, even with a 65mm lens.

FWIW, the most-used movements with shorter focal-length lenses are rise and fall in order to correct converging verticals. The problem with a 65mm lens is that the coverage is extremely limited and you won't get much rise or fall out of it before it vignettes. The same goes for front tilts and swings. Applying a bit of back tilt to get foreground and background in focus and still use an optimum aperture is more realistic if you find the need. Otherwise, just stop down, keeping in mind that apertures smaller than f/22 or f/32 will introduce a bit of degradation due to diffraction. I won't print larger than 11x14 from a 4x5 negative that was shot at f/45 and even then you can see a bit of softness due to diffraction. f/22 is where most lenses perform best; I find f/32 a good compromise in most situations.

And, you can always use tilts to selectively de-focus areas of your image; the same caveats apply.

About center filters: If you shoot color transparency film, you'll probably want one of these. If, like me, you shoot black-and-white negative film, you can correct the light fall-off in printing; just remember to give the negative another stop of exposure to compensate for the fall-off if you need shadow detail at the edges.

Best,

Doremus

wow - these centre weighted filters are more expensive than my camera and lenses! I think I'll have to stick to using Lightroom filtering on the scan. Seems a lot more flexible to me and cheaper too.
Alan

[Lachlan 717]

It's not more flexible, as it complies to the SI/SO* rule.

You still need a quality scan of a quality image. You might/can get by with some neg film; you won't get by with most positive film.

Digital processing is NOT a silver bullet.

*Shit in/Shit out.

[Mick Fagan]

Of course, these centre weighted filters aren't easy to get. I'm in Australia and no local suppler has them So they're costly.
But surely the centre diameter of the filter is also an element to consider? Do they come in varying weights and centre diameter fall-offs? Using one at f/45 must be very different to using one at f/5.6. My (lack of) knowledge of optics might be failing me here.
Alan

Are you near Melbourne? If so, we could meet up and you could try mine, or at the very least look through the ground glass.

They are not cheap, but second hand they are around and can be surprisingly well priced. I picked mine up from Australia at a reasonable to me price, you just have to know if you want something, then wait for the correct to you price, to pop up.

They are available new locally, however with the Australia tax, they are prohibitively priced. I know as I priced and sourced them locally.

Just looking through the ground glass will give you a very good idea of the difference with the Fujinon f/5.6 SWD 65mm and a centre graduated filter attached and not attached, it is that noticeable with that lens.

Mick.

[Lachlan 717]

I've got a test shot comparison using a 72mm SAXL somewhere, shot down in the Otways. I'll try to find it. It clearly shows the difference in image quality. One was usable; one was not. Huge difference.

[LabRat]

Another good thing about using a center filter is if your film has a severe reciprocity effect, and you shoot in dimmer light without one, the falloff can be exaggerated at tiny stops/longer times...

Steve K