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-   -   50mm with most uniform bokeh (and a big front?) (http://www.rangefinderforum.com/forums/showthread.php?t=169810)

redimp 10-22-2019 13:52

50mm with most uniform bokeh (and a big front?)
 
Hey guys, I'm looking for a 50mm (45-60 range) rangefinder lens that would have the most uniform bokeh.

There is this effect that people refer to as "cat's eye bokeh" or "bokeh lemons", I also saw people call it "bokeh vignetting".

Essentially the front element of the lens is big enough to not cause vignetting of the image itself, but small enough to cause vignetting in bokeh, and sort of "cut off" specular highlights (bokeh balls).

This results in a certain effect that combined with field curvature creates a bokeh "swirl".

Field curvature, that also is sometimes referred to as "undercorrected petzval" is another effect that causes bokeh balls closer to the edge of the projected circle (and the frame) to distort and compress along the radial axis of the image circle.

I'm looking for a lens that does not have these effects, or has them well corrected.

I know that stopping down really helps to reduce it because your entrance pupil gets smaller in correlation to the front element. There is this discussion I found that has a lot on the topic https://photo.stackexchange.com/ques...m-bokeh-effect

I am looking to adapt this lens to panasonic s1H, that's why I'm looking for a rangefidner lens to keep the setup compact, but if anyone knows of an SLR lens that fits the description please let me know.

So if the lens is slow-ish, like 50 2 or 50 2.8 I'm more then fine with it, even if it's a 50 3.5.

Another option is to get a very fast lens, like 1.2 that has a lot of aperture blades, and just stop it down to 2.4 or 4, but the aperture count has to be like 10+ to keep the bokeh round.



I would appreciate any suggestions on the lens, I am also interested in longer focal lengths to make a set, something like 50, 80, 115, etc.

Thank you for your advice!

d__b 10-22-2019 14:17

I don't have a specific suggestion but I wonder if lenses designed for a larger image circle might help. Like medium format lenses. That way you would potentially be cropping off the part of the image where the bokeh starts misbehaving...

helenhill 10-22-2019 14:22

I would recommend the 50 Elmar M f2.8 made around 1990 methinks
or the Sumnarit 50 2.5
Both render beautifully, soft bokeh, not swirly or over piwering in an Image
Will post photos when I get home

Erik van Straten 10-22-2019 15:23

I find this a nice bo ke. Uncoated lens.

Leica IA (1928), Elmar 50mm f/3.5, 400-2TMY/Adox MCC 110.

Erik.


Huss 10-22-2019 17:08

Zeiss ZM Planar 50 f2 has no fall off after 2.8 and has nice smooth bokeh.

goamules 10-22-2019 17:32

Somewhere there is a link to a site that shows bokeh of dozens of lenses. You can search through the examples and pick what you like.

Erik van Straten 10-22-2019 17:39

Quote:

Originally Posted by goamules (Post 2919525)
Somewhere there is a link to a site that shows bokeh of dozens of lenses. You can search through the examples and pick what you like.

This is it:

https://flashbackcamera.jp/photogall...ist_type=alpha

Archiver 10-22-2019 18:36

Zeiss ZM C Sonnar 50mm f1.5. No cats eye, circular specular highlights, smooth and pleasant bokeh. The only issue is some chromatic aberration wide open and the focus shift at f1.5.

redimp 10-23-2019 11:12

Quote:

Originally Posted by Erik van Straten (Post 2919526)

This is very helpful, thank you.

Rob-F 10-23-2019 13:21

50mm collapsible Summicron. Very nice background,
wide open.

helenhill 10-23-2019 13:41

BOTH Shots 50 2.5 Summarit on digital M8



a wink and a Smile...Musing with Cinematographer JM
by Helen Hill, on Flickr





The Smile... Espresso and Rachel
by Helen Hill, on Flickr

helenhill 10-23-2019 13:44

50 2.8 Elmar M modern version Film... look a tad more punchier , modern , love the greys to blacks




Afternoon snooooze...
by Helen Hill, on Flickr





Rock Me...
by Helen Hill, on Flickr


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