Rectilinearity of 35mm Summarit-S

[Pieter12]

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I need to do some copy work of fairly large weavings and I don't have a lot of room to work with--basically I can place the camera 6 or 7 ft from the weaving. The Summarit-S 35mm f/2.5 ASPH will cover the area I need, but without doing any testing myself beyond casual observation of a similar-size subject with rectilinear features at the same distance I wonder if anyone has any experience or can point me to some information about distortion with this lens. I am not concerned about the far edges along the long side since the weavings are approximately 4:5 proportion. I'd rather not have to do much correction in post, I use Capture One or Photoshop.

[LeicaR10]

Pieter12

You should not have any issue with photographing thw weaving.  The weaving should be perpendicular to the camera.  Here is the Leica technical data sheet for the lens.  

Try:  https://leica-camera.com/en-AU/photography/lenses/s/summarit-s-35mm-f2-5-asph    The lens is optically superb. I would shoot in manual focus at f/8 to get the detail.

The S camera uses no internal firmware for corrections.  All S lenses are optical engineering marvels.  Your post processing software may offer some correction, but its minimal.

Happy New Year!  r/ Mark

Edited December 27, 2022 by LeicaR10

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[Pieter12]

Thank you. It's appreciated.

[Stuart Richardson]

The 35mm does have a bit more distortion than most of the S lenses, but it is still quite low. As Mark noted, it is an optically superb lens. That said, this is one of the cases where using the lens profile correction in Photoshop will be useful. Make sure that it is also correcting for distortion, not just vignetting. I am not sure if Capture One has a lens profile for this lens, but Photoshop and Lightroom certainly do.

I have posted this photo before, so apologies if it gets repetitive, but here are two versions of the same photo, one with distortion correction on, one with it off. This is not upright perspective, just the lens profile correction. The difference is easier to see in the program when you are checking the box on and off. You may need to open them in windows where you can see them side by side.

 

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Edited December 28, 2022 by Stuart Richardson

[Pieter12]

Thanks. I downloaded the images and stacked them in layers in Photoshop and can clearly see the (slight) difference by turning the top layer on and off. The file also has the lens profile in it, I will take advantage of that. Not sure where to get lens profiles otherwise.

[Stuart Richardson]

The profiles are typically carried in the program, not the lens. At least for these older lenses. So typically the EXIF will just tell the program which lens profile to choose, but in the case of manual lenses, you can just choose the correct profile. For some more modern digital only lenses, the lenses themselves carry the correction information, but it is really just a set of instructions for the raw converter.

[jip]

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A recent copy of Lightroom will apply the lens profile automatically to compensate distortion.

[davidmknoble]

@Pieter12, I know this is not what you asked, but depending on how important the distortion is to you, have you considered using the 45 or 70 (which have almost negligible distortion compared to the 30 and 35) and stitching together muliple images from a longer focal length?  It sounds like it is a tradeoff either way...

[Pieter12]

It's done now. The weavings were not hung, and had to be shot on the floor. I did not have the room to get the entire weaving in the frame with the 70mm. And I did not want to stitch--there were  23 weavings plus another 45 pieces to photograph. Luckily, I have a tripod that will reach over 6' and used a horizontal arm to make a copy set-up.

[davidmknoble]

18 hours ago, Pieter12 said:

It's done now. The weavings were not hung, and had to be shot on the floor. I did not have the room to get the entire weaving in the frame with the 70mm. And I did not want to stitch--there were  23 weavings plus another 45 pieces to photograph. Luckily, I have a tripod that will reach over 6' and used a horizontal arm to make a copy set-up.

Glad it got done!  Sounds like a big job….