Rangefinder Lenses

[andyw]

Just as a heads up really.....

I find that Rangefinder lenses are far smaller than the normal adapted lenses and they suit the GF1 and Pen far better. I have a Voigtlander 35mm which look like it belongs on the camera size wise. When searching for rangefinder lenses on ebay is interesting what gets thrown up.

 

[Brian Mosley]

Hi Andy,

I agree, but am I right in thinking that the registration distance usually being shorter... there are more problems with corner smear?

Is this something likely to occur with most rangefinder lenses, just the wide angle ones (i.e. 28mm and wider) or does it vary from lens to lens?

Cheers

Brian

 

[sebastel]

hi brian,

corner smear is most apparent at short focal lengths - 28mm and shorter - and also depends on the lens itself. for example when comparing the 25mm biogon to the 25mm skopar, the biogon shows a little more smearing.

regards,
sebastian

 

[Iansky]

Yep - those rangefinder lenses compliment the GF1 really well.

I have only tried my 50 so far but have the 28 & 90 yet to try

 

[chalkdust]

The corner problem is also helped out a bit in micro four thirds because our sensor is smaller than these lenses were designed for. So our corners are not as far from the center as they would be in 35mm format. I have not found any objectionable issues with RF lenses from 21mm to 90mm focal length.

 

[mabelsound]

The corner problem is also helped out a bit in micro four thirds because our sensor is smaller than these lenses were designed for. So our corners are not as far from the center as they would be in 35mm format.

You would think that would help, but it doesn't seem to be the case. The photosites on the m4/3 sensor are just not made to receive oblique light rays, as, say, those on the Leica M8 and M9. So there are very few RF wides that do not show smeared corners, in spite of the smaller sensor. If it was APS-C, it would be even worse. Everything 50mm and up works marvelously, though.

I don't find the smeared corners particularly objectionable a lot of the time, either, though--the CV 15mm is quite handy on the GF1, and I think its manual focus and distance scale trump the corner problems (which ultimately are not all that bad).

I do wonder if the Samsung NX10 is going to disappoint a lot of people hoping to use it as an M8 substitute...I doubt the sensor is optimized for rangefinder lenses.

 

[cosinaphile]

i believe a design issue precludes using any m mount on the samsung at all i actually look foward to an aps sensor m mountable machine

 

[Brian S]

The lenses available for the Micro 4/3 share more with RF design because of the lack of mirror. Otherwise, the 17mm and 20mm lenses would be retro-focus designs. Compare a Nikkor 20/3.5 with the 20mm lens available in micro-4/3rds. That is where the Crop factor comes in: the corners on a 35mm full-frame are much farther from center than a 4/3rds sensor.

 

[mabelsound]

So Brian, how do they manage to keep the corners relatively sharp with the 20/1.7? If I remember right, the corners are actually that lens's main weakness, but they are much better than with M-mount wides.

 

[chalkdust]

I have not been able to find an answer to this question, "is the Panasonic 20mm f1.7 a retrofocus lens design?"

Meanwhile, I decided to try the bookshelf test on my M mount lenses along with the kit lens (14-45mm) on my G1.

Disclaimers:
1. These are not perfect tests, but every lens was tested with the tripod in exactly the same place. So they all got the same imperfections.
2. What I am reporting as sensor smear could have been other optical characteristics of the lenses. But it LOOKED like smear - directional if you know what I mean.
3. How important are Bookshelf Pictures to anybody anyway?
4. I am no expert.

Results:
21mm f2.8 Zeiss Biogon smear
28 mm f1.9 Ultron smear
14-45mm Panasonic at 14mm sharp
35mm f1.2 CV Nokton smear
50mm f3.5 CV Heliar sharp

I hope I am not stirring up a hornets' nest. I really LIKE all of these lenses!

 

[chalkdust]

I got to thinking about my depth of field. Especially since the bookshelf is a flat field. So I redid the three tests that came out "smear" above but this time at f8.

This time, only the 21mm Biogon showed a little bit of what could be smear at the edge.

The others were very sharp.

Same disclaimers still apply.:smile:

 

[Brian S]

So Brian, how do they manage to keep the corners relatively sharp with the 20/1.7? If I remember right, the corners are actually that lens's main weakness, but they are much better than with M-mount wides.

I am just going to have to buy one (for my wife of course) and find out! I suspect the image circle is larger than what is required for the 4/3 sensor. As far as being a retrofocus design, look through the back of the lens and then turn it around. If the view through the lens looks about the same, it's not a retrofocus.

 

[OzRay]

One of the things Olympus pushed from the very start with 4/3s was it's tele-centric lens design and I think that there was some truth to that assertion, as every lens seemed to be clear and sharp right up to the edges. When m4/3s came out, this tele-centricity aspect was posed to them in some article and, while I can't remember the exact response, it was to the effect that things had moved on and Olympus wasn't pushing tele-centricity with m4/3s.

I haven't really done any tests with my rangefinder lenses to see whether edge smear is an issue, but having a look at some shots taken with the Voitglander 15mm f4.5, it's a bit of a mixed bag. Some shots look good, others have quite evident corner smear and edge smear, while others only have some mild corner smear. Go figure. But then, I don't always worry too much about these things, as it's the image itself that's often more important than some technical deficiency.

Cheers

Ray

 

[Brian Mosley]

Go figure. But then, I don't always worry too much about these things, as it's the image itself that's often more important than some technical deficiency.

Cheers

Ray

Thanks for this, Ray... I'm trying to 'detox' from the dpreview forum obsession for tech specs and focus more on photography moving forward - at least in this space . Obviously, it's a balance - but m4/3rds is the best compromise I've found so far.

Cheers

Brian