Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
11-12-2013, 05:52 AM   #1
Inactive Account




Join Date: Oct 2013
Posts: 249
flange FD / register - what can be adapted?

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.

11-12-2013, 07:38 AM   #2
Site Supporter
boriscleto's Avatar

Join Date: Dec 2009
Location: Liverpool, NY
Photos: Gallery
Posts: 12,279
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.
11-12-2013, 07:43 AM   #3
Inactive Account




Join Date: Oct 2013
Posts: 249
Original Poster
QuoteOriginally posted by boriscleto Quote
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.
11-12-2013, 01:36 PM   #4
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,312
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


Last edited by Lowell Goudge; 11-13-2013 at 05:08 AM.
11-12-2013, 06:58 PM   #5
Inactive Account




Join Date: Oct 2013
Posts: 249
Original Poster
QuoteOriginally posted by Lowell Goudge Quote
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?
11-13-2013, 05:02 AM   #6
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,312
QuoteOriginally posted by tripodquest Quote
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
11-13-2013, 05:05 AM   #7
Inactive Account




Join Date: Oct 2013
Posts: 249
Original Poster
QuoteOriginally posted by Lowell Goudge Quote
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...
11-13-2013, 05:12 AM   #8
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,312
Note I corrected the link, check again the list of regestry distance

Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
extension, k-mount, lens, lenses, optics, pentax, pentax lens, pk, slr lens, tube
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Can Nikon Ai and/or non Ai lenses be adapted to work on the K mount? Vantage-Point Non-Pentax Cameras: Canon, Nikon, etc. 3 07-28-2013 08:25 PM
Can Nikon lenses be adapted to Pentax? slackercruster Pentax SLR Lens Discussion 15 04-17-2012 05:05 AM
For Sale - Sold: DA21 f/3.2, Canon FD 300mm f/4 Kmount Adapted adpo Sold Items 6 03-08-2012 12:27 AM
Can Zeiss (Nikon or Canon) mount lenses be adapted to Pentax? slackercruster Pentax SLR Lens Discussion 4 02-13-2012 12:47 AM
Where to measure canon fd flange focal distance? ripit Pentax SLR Lens Discussion 2 01-22-2012 09:29 AM



All times are GMT -7. The time now is 11:40 PM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top