# Raw Therapee shows a smaller focal length than lightroom



## lightroomer (Feb 24, 2013)

Hi,

I own a Canon S100. This cam is able to store the RAW file to the SD. I took a picture with 24 mm focal length.

When I open this RAW file with Raw Therapee I can see the picture with the typical lense distortion. After the lense correction I have a folcal length of round about 21 mm!!!

When I open this RAW file with Lightroom I can see the picture with exact the same focal length as the JPEG file has (24 mm) and there is no distortion at all in that RAW file. I double checked in Lightroom if there is a lense profile applied but it is not. Therefore my question: Is it possible to get the same results from RAW Therapee in lightroom? Do I need to create my own lense profile then?


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## Hal P Anderson (Feb 24, 2013)

LR is probably automatically removing the lens distortion on files from that camera. It does that on my Canon S90. AFAIK, there's no way to turn it off. 

Hal


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## lightroomer (Feb 24, 2013)

*AW: Raw Therapee shows a smaller focal length than lightroom*

Oh no, then Lightroom removes some valuable data. One is able to have a really useful focal length of 21 mm. Is there really no workaround? Maybe it is possible to change the raw file e. g. by using chdk?


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## lightroomer (Feb 25, 2013)

Does no one knows a workaround?


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## Victoria Bampton (Feb 25, 2013)

I'm not sure I quite follow the problem - what metadata are you saying LR's removing?


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## lightroomer (Feb 25, 2013)

Hi Victoria,

there is no metadata been removed but there are pixels removed which would increase the focal length.

Here is a screenshot:
https://www.dropbox.com/s/woj4dt6wmz9lqek/Lightroom - RawTherapee.JPG

The screenshot shows the right part of the picture. On the left hand side you can see the picture opened in lightroom, on the right hand side you can see the picture opened in RAW Therapee (the distortion is not corrected, yet)


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## Victoria Bampton (Feb 25, 2013)

I'm with you!  No, there isn't a way to turn that off in LR - I believe there are agreements in place with the manufacturers for certain cameras.  What does the camera do with a JPEG?


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## lightroomer (Feb 25, 2013)

*AW: Raw Therapee shows a smaller focal length than lightroom*

The camera creates a jpeg with exactly the same focal length as LR does. 

Isn't it possible to change something in the converter (maybe it's an XML file)? 

BTW: I have a similar thread running here:

http://forums.adobe.com/message/5101464#5101464

I thought it is another channel.


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## Kiwigeoff (Feb 25, 2013)

If that is the result that Canon gives there is a purpose. Why should Adobe do something different?


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## lightroomer (Feb 26, 2013)

*AW: Raw Therapee shows a smaller focal length than lightroom*

This is the trick: I own also an SX230 which is actually not able to write  raw files. But by utilising chdk it was able to write a dng file. This is naturally not supported by Lightroom. Nevertheless there were some guys out there who created a lense profile for this by using Adobe lense creator (don't know if this is the official name of the tool). 

I realised that this methodology brings back some hidden pixels which is (especially in wide angle pictures) a vital advantage over the jpeg: it decreases the focal length even further from 28 mm (which is the official lowest focal length of the SX230) to 24 mm. IMO Canon crops the picture a lot more to ensure that no black corners from the lense distortion appear in the resulting picture. Nevertheless, the applied lense profile removed also the black corners from the dng image and furthermore it showed more pixels than the jpeg does which is in fact a wider focal range. 

Now I tried the same with the S100. The difference here is that the raw file is officially supported and Lightroom applies the same rules as canon's built in development does. What a pity, since I can't benefit from the real sensor data any more. Other tools like raw therapee does not do this. But I don't want to haven another tool in my workflow.


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## bobrobert (Feb 26, 2013)

You keep saying it is focal length which  - imo - is confusing because I think you mean field of view?


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## lightroomer (Feb 26, 2013)

*AW: Raw Therapee shows a smaller focal length than lightroom*

What is the difference between focal length and the field of view?


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## bobrobert (Feb 26, 2013)

The focal length you took the image at remains unchanged even if you crop an image. What you are trying to describe in your post that some kind of cropping has taken place. However when you crop an image then the field of view - FOV - changes. It becomes less. This is assuming that I am reading your posts correctly. A Google search will explain it better than me.


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## lightroomer (Feb 26, 2013)

OK, you might right. From my perspecitve (as a beginner in photography) there is no difference. Cropping is for my something similar as digital zoom which is an increase in focal length.

To transfer this fact to this problem: LR (as well as the Canon built in development process) removes pixel which would decrease the focal length or better increase the field of view. And this is clearly a benefit to the jpegs which the Canon cam produce. It would be very nice to influence LR's development process to make these pixel visible again.


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