50mm 1.7 Pentax-M vs Pentax-A

newarts · 05-07-2012, 01:21 PM - **1 Like**

Originally posted by pezmaker

There are some clip ins, but at the very least you'd still need to take some pliers or something and straighten it out. CAUTION - this may wreck the the threads more. If you're careful and use cardboard or something to keep from screwing up the threads, you may be able to get this to the point where you can use a filter to help straighten it even more. I have a takumar 50 f1.4 that has dinged filter threads from what looks to have been a similar ding, but I can put my hood or filters on it after whoever had it before me straightened it.

So, in essence, not all is yet lost, but it oculd take some work, and you may need to be careful. I

One thing to think about, is taking the glass out of a really cheap filter and putting that filter on the lens as a permanent filter thread replacement. Screw it on anyway you can, maybe locktite it in place, and now you've got good filter threads again.

There are a number of ways to do this ranging between:

fast & crude: cut out the bent part & glue in a uv filter with no glass or a step-up/down ring if you prefer.

Slow & elegant : make a wood cradle with the same curvature as the outside radius & a piece of a wood cylinder. Use the cylinder to shove the bent threads back against the wood cradle; this will protect the threads from too much damage. Do this until a step-up/down ring can be threaded in and glued in place.

EDIT:
Easier & pretty elegant: tighten a screw tightening type stainless steel hose clamp around the outside of the bent filter ring. This will be the form to guide the bent part of the ring as you squish it back into place. Use a piece of hard rubber, soft plastic, etc between the plier jaws and the filter threads.

I suppose one could cut out a section of another filter ring to use as a buffer between the pliers and bent ring - this should complete prevent munging the inside threads on the bent part if the threads are meshed before pressure is applied. This may result in a repair so good it does not require a new threaded ring to be glued in place.

Dave

Last edited by newarts; 05-07-2012 at 02:17 PM.

alphanerd · 05-07-2012, 04:10 PM

Originally posted by V10

You can use a longer hood when using a 50mm on a crop body. The hood from the Takumar 135mm 3.5 works perfect.

I can vouch for this. I use my m42 takumar 135mm f3.5 hood on my 50mm f1.7 lens, and I can't see any vignetting. It does double the length, though.

Kaufeetime · 05-09-2012, 07:54 AM

As with any camera repair work gently and slowly. Consider using a lens filter ring vise sold by Micro-Tools. The second option is found on the repair forum of kyphoto.com.
There are pro and cons to each option, so choose carefully.

SenorBeef · 05-09-2012, 01:45 PM

There are no hoods that just slip on to the end of the lens barrel (maybe with a clamp or something) rather than screwing into the threads?

pinholecam · 05-09-2012, 07:03 PM

I had both, as well as the f2 and f1.4.
I never say any difference in sharpness on them between M and A versions.

I prefer the M versions which are slightly smaller in physical look and feels nice with less plastic. The A series always felt more wobbly on the aperture ring and plasticky on the focusing ring.
However, I sold the M as A series are easier to use. Av mode, PTTL support, EXIF data are all creature comforts over the M.

Get a hood. There are plenty of cheap ones on ebay.

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05-07-2012, 01:21 PM - 1 Like	#16
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Originally posted by pezmaker There are some clip ins, but at the very least you'd still need to take some pliers or something and straighten it out. CAUTION - this may wreck the the threads more. If you're careful and use cardboard or something to keep from screwing up the threads, you may be able to get this to the point where you can use a filter to help straighten it even more. I have a takumar 50 f1.4 that has dinged filter threads from what looks to have been a similar ding, but I can put my hood or filters on it after whoever had it before me straightened it. So, in essence, not all is yet lost, but it oculd take some work, and you may need to be careful. I One thing to think about, is taking the glass out of a really cheap filter and putting that filter on the lens as a permanent filter thread replacement. Screw it on anyway you can, maybe locktite it in place, and now you've got good filter threads again. There are a number of ways to do this ranging between: fast & crude: cut out the bent part & glue in a uv filter with no glass or a step-up/down ring if you prefer. Slow & elegant : make a wood cradle with the same curvature as the outside radius & a piece of a wood cylinder. Use the cylinder to shove the bent threads back against the wood cradle; this will protect the threads from too much damage. Do this until a step-up/down ring can be threaded in and glued in place. EDIT: Easier & pretty elegant: tighten a screw tightening type stainless steel hose clamp around the outside of the bent filter ring. This will be the form to guide the bent part of the ring as you squish it back into place. Use a piece of hard rubber, soft plastic, etc between the plier jaws and the filter threads. I suppose one could cut out a section of another filter ring to use as a buffer between the pliers and bent ring - this should complete prevent munging the inside threads on the bent part if the threads are meshed before pressure is applied. This may result in a repair so good it does not require a new threaded ring to be glued in place. Dave Last edited by newarts; 05-07-2012 at 02:17 PM.

05-07-2012, 04:10 PM	#17
alphanerd Senior Member Join Date: Mar 2011 Posts: 119	Originally posted by V10 You can use a longer hood when using a 50mm on a crop body. The hood from the Takumar 135mm 3.5 works perfect. I can vouch for this. I use my m42 takumar 135mm f3.5 hood on my 50mm f1.7 lens, and I can't see any vignetting. It does double the length, though.

05-09-2012, 07:54 AM	#18
Kaufeetime Senior Member Join Date: Sep 2009 Location: Kansas City,Mo. Photos: Albums Posts: 206	As with any camera repair work gently and slowly. Consider using a lens filter ring vise sold by Micro-Tools. The second option is found on the repair forum of kyphoto.com. There are pro and cons to each option, so choose carefully.

05-09-2012, 01:45 PM	#19
SenorBeef Forum Member Join Date: Mar 2012 Location: Las Vegas Posts: 77 Original Poster	There are no hoods that just slip on to the end of the lens barrel (maybe with a clamp or something) rather than screwing into the threads?

05-09-2012, 07:03 PM	#20
pinholecam Pentaxian Join Date: Oct 2009 Location: North Photos: Gallery Posts: 4,709	I had both, as well as the f2 and f1.4. I never say any difference in sharpness on them between M and A versions. I prefer the M versions which are slightly smaller in physical look and feels nice with less plastic. The A series always felt more wobbly on the aperture ring and plasticky on the focusing ring. However, I sold the M as A series are easier to use. Av mode, PTTL support, EXIF data are all creature comforts over the M. Get a hood. There are plenty of cheap ones on ebay.