# Use lens correction for pictures planned for stitching?



## bluenoser1993 (Dec 20, 2014)

Just wondering if anyone has tried using the in camera lens distortion correction (or CPP) for a sequence of shots planned to be used in stitching software (i'm using ptGui) as compared to just using straight out of camera files? I'm guessing it adds one more opportunity for image degradation, as the software will still have to correct for the FOV distortion, but I'm wondering if starting with distortionless images will help the elements within the final picture be more true to form.

I'm going to the final 49ers game of the season and want to do a pano from my seat of the stadium/side line activities /and a shot that includes a play on the field that will be the centre of the stitch.

With NFL rules the easiest thing is to have the 7DII hanging on my shoulder with the 135L mounted and the pancake 40mm in my pocket. I'll be in row 1 around the 25, so the 40 should be able to capture a whole play as long as I do it while occurring in a strategic part of the field.

One of those things that you only get one chance at. I think I'll use high speed and snap a few shots of each frame to ensure I get choices for better blending of frames.


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## agierke (Dec 20, 2014)

a while back i did some stitching of some panos where i applied lens correction to the files in ACR before stitching them together. i recall there being additional smearing/ghosting of details around where the edges of each frame overlapped (more so than when i just stitched straight out of camera shots).

im not sure but its possible software will take into account lens distortion in the algorithms used to stitch shots together. don't quote me on that.. 

maybe having the lens correction done in camera will circumvent the sloppy blending i experienced when i used ACR to do lens correction. not sure. you can very easily do the test yourself in a few minutes.


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## Marsu42 (Dec 20, 2014)

bluenoser1993 said:


> I'm guessing it adds one more opportunity for image degradation, as the software will still have to correct for the FOV distortion



*If* its just a fov distortion, and not a complex one - and esp. dxo corrects for much more than that. Plus the lens profiles at least in acr take care of vignetting and CA, too - however, stopped down that won't be a problem. 

Personally, I always apply lens profiles and basic post-processing in ACR before sending the frames off to the stitching software. I'm not a wiz at stitching, but it works just fine this way esp. since I always downsize the stitched shot anyway ... what's the use of a 100+ megapixel panorama to the average layman?


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## bluenoser1993 (Dec 20, 2014)

Thanks for the ideas, with the time of year and 4 kids I may or may not have the time to play with my new toys. I haven't had a chance to fool around with the distortion correction in the 7DII yet. If I don't find the time to experiment, I think I'll just stick with what I know what works for now. Come to think of it, the RAW files will give me a chance to process it both ways and compare the results from the same set of shots.


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## agierke (Dec 21, 2014)

> Come to think of it, the RAW files will give me a chance to process it both ways and compare the results from the same set of shots.



that is what i was suggesting. good luck. im pretty sure it wont be as difficult as you may think


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## Aichbus (Dec 22, 2014)

I recommend shooting RAW in any case. Regarding the stitching issue, there are programs out there that can do the correction while stitching. The also use lens profiles and if they do the correction and the stitching it in one go, they maintain the image quality more than other programs that don't. I don't know about ptgui, but for Autopano Giga I know that this is the case. Apart from that I am using Microsoft ICE a lot for stitching a small number of images, mostly with architectural motifs. And there I found that i need to correct the distortion of my 70-300 L @ 300 mm beforehand. Otherwise I don't get straight lines in my result. I don't nee need a correction for my Tamon 3.5 180 mm Macro, my EF 2.8 200 L, my 4 500 L and my 4 600 L II.


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