Home

Please support mflenses.com if you need any graphic related work order it from us, click on above banner to order!
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

Using M42 manual lenses with adapters
Post new topic   Reply to topic
Home   Manual Focus Lenses
View previous topic :: View next topic  


PostPosted: Mon Feb 23, 2015 8:38 am    Post subject: Using M42 manual lenses with adapters Reply with quote
I have used two different M42 to Sony NEX adapters with two different soviet manual lenses and infinity focus matches the marks on the lenses. Is this the case with all M42 lenses, soviet M42 lenses or have I been just lucky?

Is it a good idea to leave an M42 lens that has a diaphragm pin on a camera body using an adapter with a flange? Will this cause a problem to the lens in the long run since the inner flange of the adapter will push down the diaphragm pin permanently?


PostPosted: Mon Feb 23, 2015 9:32 am    Post subject: Reply with quote
If the distances match perfectly you have been quite lucky. Almost all the m42-nex adapters I've had worked just fine, many go a little bit past infinity - which is something I don't dislike. Keep in mind that old lenses themselves are not always perfect: sloppy quality control, repair attempts, damages or simple time passing may have altered the exact distances by some fraction of a millimeter, so not only adapters are to blame, and having a bit of margin to compensate with the adapter may be useful. As for the pin, I jammed quite a lot over time (flanged adapters didn't work well with some lenses), and the ones I unjammed work fine now, but I wouldn't exclude that leaving it pressed all time for a long period may somewhat affect the spring.


PostPosted: Mon Feb 23, 2015 8:11 pm    Post subject: Re: Using M42 manual lenses with adapters Reply with quote
kyrcy wrote:

Is it a good idea to leave an M42 lens that has a diaphragm pin on a camera body using an adapter with a flange? Will this cause a problem to the lens in the long run since the inner flange of the adapter will push down the diaphragm pin permanently?


That depends on the lens. For those that are pin-less with pre-set apertures, it is a non-issue.

For those that are designed to be forced open in order to make focusing easier, one would hope that the spring is strong enough to let the lens sit on a camera for a long time without losing strength.

For those lenses with an A-M switch, I recently made an interesting discovery. The ledge that pushes the pin in the M42 adapters I have are not machined into the body, but rather are formed by a washer-like disk that is inserted between the threaded receiver and the body of the adapter. When that is the case, it is possible to loosen the set screws a little more than needed to adjust the lens orientation, remove the threaded part and the washer, and then replace the threaded part and re-tighten it. The groove around the threaded ring should hold it at the correct flange distance. This can also be useful with lenses that have a male thread that is slight longer than normal, allowing the flange of the lens to mount flush with the shoulder of the adapter.

HTH


PostPosted: Mon Feb 23, 2015 8:39 pm    Post subject: Reply with quote
Springs do not lose strength by prolonged compression. They lose strength by cycles of compression.


PostPosted: Tue Feb 24, 2015 6:13 pm    Post subject: Reply with quote
Welcome kyrcy!


PostPosted: Tue Feb 24, 2015 6:13 pm    Post subject: Reply with quote
dabsond wrote:
Springs do not lose strength by prolonged compression. They lose strength by cycles of compression.


Do you mean that it is better leaving the lens permanently on the adapter even if it is pushing down the diaphragm pin (prolonged compression) instead of screwing the lens on the adapter every time (cycle of compression)?


PostPosted: Tue Feb 24, 2015 9:50 pm    Post subject: Reply with quote
I don't think you have much to worry about, most of the springs I've seen in M42 lenses could survive millions of compressions, heat and pushing the spring past its intended design are by far the quickest way to damage a spring.


PostPosted: Wed Feb 25, 2015 12:33 am    Post subject: Reply with quote
visualopsins wrote:
Welcome kyrcy!


Thanks.


PostPosted: Wed Feb 25, 2015 1:21 am    Post subject: Reply with quote
kyrcy wrote:
dabsond wrote:
Springs do not lose strength by prolonged compression. They lose strength by cycles of compression.


Do you mean that it is better leaving the lens permanently on the adapter even if it is pushing down the diaphragm pin (prolonged compression) instead of screwing the lens on the adapter every time (cycle of compression)?


Don't you take your lens off the adaptor? I think mine stay on as long as I need them to. Then they are back on the cameras or in their case.


PostPosted: Wed Feb 25, 2015 1:43 am    Post subject: Reply with quote
philslizzy wrote:
Don't you take your lens off the adaptor? I think mine stay on as long as I need them to. Then they are back on the cameras or in their case.

By taking the lens off the adapter and putting it on again and then on the camera body I think there is a risk of scratching the lens mount and exposing the sensor to dust.


PostPosted: Wed Feb 25, 2015 4:07 am    Post subject: Reply with quote
philslizzy wrote:
kyrcy wrote:
dabsond wrote:
Springs do not lose strength by prolonged compression. They lose strength by cycles of compression.


Do you mean that it is better leaving the lens permanently on the adapter even if it is pushing down the diaphragm pin (prolonged compression) instead of screwing the lens on the adapter every time (cycle of compression)?


Don't you take your lens off the adaptor? I think mine stay on as long as I need them to. Then they are back on the cameras or in their case.


I have a dedicated adapter for each lens. They have programmable chips for exif data.


PostPosted: Wed Feb 25, 2015 4:19 am    Post subject: Reply with quote
Blow the dust off the sensor.
I have had three Pentax DSLRs - K100D, K-x, K-30

1 and 2 have taken, each, about 250k actuations and I have used hundreds of lenses on them.
1 still works fine, its just obsolete, 2 was destroyed by repeated soaking in water. 3 is up to 70k actuations.

Unless you are working in a very dusty environment I wouldn't worry about changing lenses.


PostPosted: Wed Feb 25, 2015 3:25 pm    Post subject: Reply with quote
On original camera, M42 lens has spring actuated every shutter time -- many more times than for changing lenses. Wink

Yes, for dslr, leaving adapter on lens will result in fewer spring actuations.

When changing lenses, keep out of the wind, keep camera "throat" pointed down, exchange lenses quickly. I live in very dusty environment, change lenses frequently -- after initial cleaning, I have not had to clean, other than blow off dust, for several years now, after thousands of photos.
Post new topic   Reply to topic
Home   Manual Focus Lenses
Page 1 of 1