Industar 61/L and L/D--Focal Length differences.

[SCOTFORTHLAD]

Just out of interest,I notice that there are small differences in the focal lengths of my I61 lenses.I have two 161L in black and chrome,which are marked as 53/2.8,while my black I/61L/D is a 52/2.8.

Any info',or theories,as to the reason for this.

Once again apologies if this has come up before.

Brian.

 

[hiwatt]

Guess what? My Industar-61 L/D (that's the Lanthanium version right?) is marked 2.8 / 55....s/n is 9411170...

 

[Spyderman]

I think all are exactly the same construction and the same focal length. It is necessary for 50mm RF lenses to be the same focal length as the camera was designed for. I think that all the Jupiters and Industars in 50mm and around are the same focal length. It's just a rounding error 🙂

 

[SCOTFORTHLAD]

I think all are exactly the same construction and the same focal length. It is necessary for 50mm RF lenses to be the same focal length as the camera was designed for. I think that all the Jupiters and Industars in 50mm and around are the same focal length. It's just a rounding error 🙂

I certainly haven't noticed any difference between the results from the lenses.Thinking about it,these differences will show up on Max's FSU.Lens Database.

 

[chenick]

I have an Industar 61 L (52mm) and an Industar 61 L/D (55mm)
The L is black and chrome and much better built
The L/D is more plasticky and cheaper built (e.g. 6 versus 10 aperture blades for the L)

I did a lens comparison and the I-61 L is ever so slightly wider... (although 3mm difference is really not noticeable)

Nick

 

[ZorkiKat]

😀

Just out of interest,I notice that there are small differences in the focal lengths of my I61 lenses.I have two 161L in black and chrome,which are marked as 53/2.8,while my black I/61L/D is a 52/2.8.

Any info',or theories,as to the reason for this.

Once again apologies if this has come up before.

Brian.

The "50" marked on lens ID rings -not just Industar lenses, but any lens as well- is at best nominal. All lenses have actual FL which are slightly or marginally longer or shorter than what its marked. 1...2 mm worth of deviation isn't going to be significant. What is more important for RF lenses is that their camming is correct.

Just see it this way: the manufacturer was just being "honest" when they labelled lenses as "37mm" or "29mm" or even "52mm" instead of the usual 35, 28, or 50 respectively. 😀
Jay

 

[SCOTFORTHLAD]

😀

The "50" marked on lens ID rings -not just Industar lenses, but any lens as well- is at best nominal. All lenses have actual FL which are slightly or marginally longer or shorter than what its marked. 1...2 mm worth of deviation isn't going to be significant. What is more important for RF lenses is that their camming is correct.

Just see it this way: the manufacturer was just being "honest" when they labelled lenses as "37mm" or "29mm" or even "52mm" instead of the usual 35, 28, or 50 respectively. 😀
Jay

Jay,
Strangely enough,my first thought when noticing the slight differences,was to think that in doing this ,the FSU factories were just being more accurate than their competitors.Perhaps a little naieve of them,but certainly not to be critiscised.

Thanks to everyone for the comments.

Brian.