[tripodquest]

So, I've found so many lenses after I started looking at lenses that weren't in PK mount (or even m42 or nikon F or the other easily adaptable ones) and I have a few questions.

Can lenses with larger FFD (52-63mm) than PK FFD be adapted? how much larger and do they need corrective optics or just stacking of enough material between the lens and the sensor/opening? Can this "stacking" be done with an extension tube? An example: Pentax FFD is about 45mm (yes yes, once you actually adapt you have to care about the fractions but not while writing a question), if I bought a lens with a FFD of 54mm and then bought an extension tube without optics that would have the correct mounts and the extension tube would put the lens 9mm further from the opening, would the lens then work normally and give a normal image like a normal lens?

If you don't do it yourself, how much does it usually cost to let someone do modifications like these? Of course it depends on the person or the business but what's your experience?

Smaller FFD can't be easily adapted if I understand correctly, and it would usually produce vignetting anyway? Not a big deal for me personally, the lenses I'm after have a larger FFD than Pentax.

[boriscleto]

Yes, this is all most lens adapters really are.

T-mount lenses for example have a FFD of 55mm, so they can be adapted to pretty much any SLR or compact camera that you can get a T-ring for.

[tripodquest]

Yes, this is all most lens adapters really are.

T-mount lenses for example have a FFD of 55mm, so they can be adapted to pretty much any SLR or compact camera that you can get a T-ring for.

Thank you for confirming that.

[Lowell Goudge]

You need to see the following link for what adaptors are available

http://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html

But if you wish to make your onw, start with a flanged M42 to K adaptor and a camera body or teleconverter as a donor for the body side mount and then it is just a question of the appropriate spacers

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Last edited by Lowell Goudge; 11-13-2013 at 05:08 AM.

[tripodquest]

You need to see the following link for what adaptors are available



But if you wish to make your onw, start with a flanged M42 to K adaptor and a camera body or teleconverter as a donor for the body side mount and then it is just a question of the appropriate spacers

the question here was more like: how many mm difference does there have to be to the pentax FFD for it to be adaptable?

[Lowell Goudge]

the question here was more like: how many mm difference does there have to be to the pentax FFD for it to be adaptable?

The answer here is not a function of distance but the diameter of the mount including any lugs on the lens, and throat of the Pentax mount. For example, M42 lenses are smaller in diameter than K Mount lenses, and have exactly the same regestry distance, the k mount adaptor is flush so it works.

Nikon lenses are within 1mm but due to the Nikon bayonette being too close to the k mount throat diameter, it takes about 12mm, which means that you need optical correction.

There is no set answer, but for any lens that has a native mount smaller than a K mount throat, any distance at all beyond the k mount regestry will work using an M42 flanged adaptor.

Note that this is for a quick adaptor. I also use flanged M5042 adaptors as a donor mount to make perminant changes

[tripodquest]

The answer here is not a function of distance but the diameter of the mount including any lugs on the lens, and throat of the Pentax mount. For example, M42 lenses are smaller in diameter than K Mount lenses, and have exactly the same regestry distance, the k mount adaptor is flush so it works.

Nikon lenses are within 1mm but due to the Nikon bayonette being too close to the k mount throat diameter, it takes about 12mm, which means that you need optical correction.

There is no set answer, but for any lens that has a native mount smaller than a K mount throat, any distance at all beyond the k mount regestry will work using an M42 flanged adaptor.

Note that this is for a quick adaptor. I also use flanged M5042 adaptors as a donor mount to make perminant changes

Oh, I think that answer helped me understand it a little better. Now off to painstaking research into what the different mount diameters are for different obscure mounts...

[Lowell Goudge]

Note I corrected the link, check again the list of regestry distance

[swestin]

You need to see the following link for what adaptors are available

Camera Mounts Sorted by Register

But if you wish to make your onw, start with a flanged M42 to K adaptor and a camera body or teleconverter as a donor for the body side mount and then it is just a question of the appropriate spacers

There is a considerably updated version of this page at https://stephen-westin.com/misc/mounts-alphabetical.html; I haven't worked at Cornell for about 15 years, and have no way to delete that page or to replace it to a link to my current Web site.

– Stephen H. Westin

[swestin]

You need to see the following link for what adaptors are available

Camera Mounts Sorted by Register

But if you wish to make your onw, start with a flanged M42 to K adaptor and a camera body or teleconverter as a donor for the body side mount and then it is just a question of the appropriate spacers

This page has been superseded by https://stephen-westin.com/misc/mounts-alphabetical.html I haven't worked at Cornell for over 15 years, and I don't have any way to replace that page to redirect it.

– Stephen H. Westin

[pepperberry farm]

This page has been superseded by Alphabetical List of Camera Mounts I haven't worked at Cornell for over 15 years, and I don't have any way to replace that page to redirect it.

– Stephen H. Westin

and welcome to PF!