I-26m and I-61 non-L/D?

[yek]

These two lenses are often underrated. However, I am a little curious about them. Why is there an "m" in the name of I-26m? What's the difference between the two lenses? They seem have different color of coating and I-26m has apperture up to 22 while I-61 non-L/D only to 16. Anything else, especially in optics?

😕

Thanks!

 

[DaveP]

According to Maizenberg, all the I-61's have L/D glass, they just didnt mark it on the early models.

 

[Philipp]

As Dave said, all I-61's have the same glass. L stands for Lanthanum, a rare earth. But D or Z referrs just to different mounts, LTM or M42. My original FED 4 manual mentions the Lanthanum glass in my non L/D I-61.

 

[wolves3012]

I was under the impression that the I-61L/D had Lanthanum glass but not the I-61. Perhaps I'm wrong on that then. As far as I can see, there's no difference between the I-61 and the I-26m in terms of construction (other than click-stops and f/16 or f/22) but I have just noticed one thing...

There is a difference in the number or iris blades. Both the I-26m examples I have have 11-blade (ish - it's hard to count them!) irises, as does ONE of my I-61 examples. The other I-61 and both I-61L/D examples have 6-bladed irises. Looks like they cheapened the later ones...

 

[Blank288]

I too have one I61 'panda' with multiple-blade-iris, and two others (later s/n)with 6 blades, just as the only I61L/D I have.
Performance of my 4 I61's, non-scientificly compared by photographing an evenly lit stock exchange page from 1m, varied quite widely, my 11-blade example being consistently the best one. Just coincidence, I suppose.

 

[yek]

Hi, thanks! You guys are so knowledgeable. 🙂

The number, 11, is an approximate, right? My copy seems have 10 blades. 😉 The click-stop is nice, but seems too tight. When I rotate aperture ring the lens almost un-mounts from the camera. Is it normal? I have managed to lubricate an I-26m, but this I-61 feels good at the focus ring, and I don't know whether it is possible to lubricate the apperture ring of I-61, since it's different.

Thanks!

 

[rxmd]

As Dave said, all I-61's have the same glass. L stands for Lanthanum, a rare earth. But D or Z referrs just to different mounts, LTM or M42.

More concrete, the "D" stands for дальномерный, or "rangefinder", and the "Z" stands for зеркальный, or "mirror", meaning SLR.

Philipp

 

[Blank288]

Hi Yek,
I didn't recount - it could definately be 10 aperture blades. My newer I61's certainly have a lot less.
I CLA'd all my I61's myself. It is an easy job. Since it is several years ago I don't remember the exact order of screws/rings to loosen, but i don't remember any problems and the aperture mechanism was IIRC quite self-explanatory.

 

[wolves3012]

Hi, thanks! You guys are so knowledgeable. 🙂

The number, 11, is an approximate, right? My copy seems have 10 blades. 😉 The click-stop is nice, but seems too tight. When I rotate aperture ring the lens almost un-mounts from the camera. Is it normal? I have managed to lubricate an I-26m, but this I-61 feels good at the focus ring, and I don't know whether it is possible to lubricate the apperture ring of I-61, since it's different.

Thanks!

Yes it was approximate - I thought it was 11 but it's not very easy to count them, so it could well be 10. No, the aperture shouldn't be that tight. I've never been beyond cleaning and lubing the focus helicoid on an I-61 so I can't advise how easy it is to get at the aperture mechanism.

 

[yek]

So, it needs a lubrication. After turning the ring for some times, it seems not that tight now, though still tight. Maybe I just got used to it. 🙂 Tighten the lens mounting a little bit more, the lens should be usable without much work. I am willing to test it first and see what I should do.

Thank you!