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PostPosted: Sat Oct 13, 2018 8:57 pm    Post subject: Reply with quote
I use two step-up rings to 49mm and screw on my Takumar lens hood. It's kind of fun adjusting the aperture by turning the lens hood.


PostPosted: Sat Oct 13, 2018 10:48 pm    Post subject: Reply with quote
KEO wrote:
I use two step-up rings to 49mm and screw on my Takumar lens hood. It's kind of fun adjusting the aperture by turning the lens hood.


Yes, a similar path to what I have done too.
Certainly makes setting the aperture easier.
Here are a couple more from yesterday
T

#1


#2


PostPosted: Sun Oct 14, 2018 12:36 am    Post subject: Reply with quote
Sciolist wrote:
Lightshow wrote:
Sciolist wrote:
fiftyonepointsix wrote:
The 50 Elmar is a nominal 51.6mm FL, the 5cm Tessar is a nominal 52.4mm Fl. The aperture of the Elmar is just behind the front element, the aperture of the Tessar is just forward of the rear element.

The I-22 and I-50 are copies of the Tessar. To use one on a Leica, it is best to adjust the main shim to align more closely with the rangefinder.



The infinity lock on my FED 50 3.5 collapsible actually locks the lens past infinity when using a M39 TO FX Adaptor. Now I have a steer on the adjustment required. Thank you Like 1 small .


The K&F adaptor I've used has an inner ring that can turn to allow your lens to centre. I wonder if I can screw it out by 0.8mm? I suppose I'll see.




If you have multiple LTM lenses that focus past infinity, you can mod a dedicated adapter to the correct thickness so you don't have to mod multiple lenses, especially if the adapter is not accurate in the first place.

Focusing past infinity is a sign that the lens is too close to the sensor, so if your adapter has an insert that used set screws to hold it in place, shimming it it super easy....



Thanks Lightshow. Yes, that's exactly what I'm hoping - that the K&F adaptor will take a shim. First thing I have to do is find a key to operate the three grub screws that appear to loosen off an inner ring. I thought I had small allen keys, but this requires even smaller.


As you need to increase the distance between the lens and image plane- you could also use a thin ring between the lens and the adapter to increase the stand-off. If this is the only lens that has the issue- use it with the thin ring. Paper or aluminum foil usually work. Other lenses will not be affected.


PostPosted: Sun Oct 14, 2018 8:33 am    Post subject: Reply with quote
uddhava wrote:
Lightshow wrote:

......Focusing past infinity is a sign that the lens is too close to the sensor, so if your adapter has an insert that used set screws to hold it in place, shimming it it super easy....


What do you use as shims?

there are lots of options, tape, paper tinfoil.... as long as it sits flat, doesn't overlap so as to preserve the geometry of the optics to the sensor.

I should add: That you remove the insert, add your shim between the insert and the adapter mount body, I like tape or aluminum foil tape because it stays where I put it. Paper is probably the easiest to source, and easy to cut.

You can make the shim a ring shape, or little sections that you stack, in this case you want at least 3 points to put the stack, preferably where the set screws are.

Last edited by Lightshow on Mon Oct 15, 2018 7:38 pm; edited 1 time in total


PostPosted: Sun Oct 14, 2018 11:34 am    Post subject: Reply with quote
From fiftyonepointsix - "As you need to increase the distance between the lens and image plane- you could also use a thin ring between the lens and the adapter to increase the stand-off. If this is the only lens that has the issue- use it with the thin ring. Paper or aluminum foil usually work. Other lenses will not be affected."


From Lightshow - "there are lots of options, tape, paper tinfoil.... as long as it sits flat, doesn't overlap so as to preserve the geometry of the optics to the sensor."


Thanks for the help folks. This is something I can try today.


PostPosted: Sun Oct 14, 2018 3:21 pm    Post subject: Reply with quote
Thanks for the information.


PostPosted: Mon Oct 15, 2018 5:57 am    Post subject: Reply with quote
Great lenses if you get a good one Smile
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