Poor stitching using RAW in photomerge

AB
Posted By
Adam_Bramley
Feb 4, 2009
Views
584
Replies
15
Status
Closed
Hi all,

I shoot with an a900 and would like to stitch the ARW RAW files it produces.

Unfortunately the results are pretty awful. No matter how I import the shots (through bridge, LR or PS4 itself) or the type of RAW (DNG or ARW, even TIFFs) the wizard will align but not stitch the photos together. Plenty of examples can be found in this flickr set:

< http://www.flickr.com/photos/35398335@N00/sets/7215761326763 4565/>

Selecting layers -> merge layers also has no effect – it simply flattens the layers without merging them.

However, I have no problems whatsoever if I first convert to JPG and then stitch. Here’s an example of that:

< http://www.flickr.com/photos/35398335@N00/3252828606/in/set- 72157613267634565/>

Converting to JPGs isn’t a satisfactory solution because I lose so much headroom in PP after the stitch.

Does anyone have any ideas how I can make PS4 produce good stitches when using RAWs?

All ideas much appreciated.
Related Tags
photomerge stitch

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GA
George_Austin
Feb 6, 2009
Photomerge will reject files having no common interface. You show 8 files with only 1&3 and 7&8 related in any way. Limit the open or highlighted files to those which overlap each other.
AB
Adam_Bramley
Feb 6, 2009
Hi George.

Don’t think you’ve quite understood me here.

The 8 files are all examples of poor stitching. Each of the 8 files shown were stitched from other files. Take a look at each of the 8 files and you’ll clearly see lines down the centre from poor stitching.

Would be interested in any suggestions!
LH
Lawrence_Hudetz
Feb 6, 2009
First of all, it looks as if the file hasn’t been flattened.

The snow scene has mismatched exposure values. If you open both in raw, you can match them close enough by eye to get an even match. Photomerge will do the final match.
LH
Lawrence_Hudetz
Feb 6, 2009
I see you have tried merge layers. Do a complete flattening instead of merge.
GA
George_Austin
Feb 6, 2009
Adam,

Sorry for the misinterpretation. The seams are blatant for the most part, but the two night-time city lights stitching examples seemed OK. Couldn’t find the seams in them. How about Larry’s suggestion re flattening?
CC
Chris_Cox
Feb 6, 2009
Adam – where can we find the original, unmerged RAW files to test?
AB
Adam_Bramley
Feb 8, 2009
Chris,

I’ve sent you a link to the 3 RAWs that I managed to stitch correctly as JPGs but incorrectly as RAWs by the email in your profile. They’re uploading as I type this – please give me a shout if you don’t get it within a few mins.

To the other participants – thanks very much for your suggestions as to exposures etc. I am ONLY having difficulty stitching RAW files. JPG files created from the RAWs with no changes stitch just fine, as can be seen in the example linked to in the first post.

I am unable to work out why PS4 works just fine with JPGs, but refuses to merge files in RAW.

I have tried flattening the document, again it flattens with the seams still visisble.
AB
Adam_Bramley
Feb 8, 2009
Hi Chris,

Just to confirm that the 3 RAWs in a zip are now uploaded. If you’re unable to access them please get in touch. They’re on yousendit.com so will only be around for 7 days before they’re taken down.

Cheers,

Adam
CC
Chris_Cox
Feb 10, 2009
Ok, I’ve got the files – we’ll look into it.
CC
Chris_Cox
Feb 10, 2009
Adam;

Apparently your photos are sort of on the edge of what can be aligned successfully. If you use the option in CS4 to deal with geometric distortion, it should work better RAW or not. The alignment will be a bit slower (because it’s looking at more parameters), but the results should be much nicer.
AB
Adam_Bramley
Feb 11, 2009
Chris,

Thanks for having a look at this. I still don’t understand how my machine will only attempt to merge JPGs, not RAWs – RAWs it only aligns. Did you manage to get a merged, seamless stitch from the RAWs? If so that’s different to my outcomes.

Adam
CC
Chris_Cox
Feb 12, 2009
Yeah, I didn’t have a problem with them. So, I’m not sure what you’re seeing exactly.
AB
Adam_Bramley
Feb 12, 2009
So it would appear that my install of PS4 isn’t functioning correctly. Is there any setting that would cause it not to merge RAW files? Could it be to do with the size of the files Vs the JPGs – would maybe explain why the TIFFs also don’t merge.

I run Vista 32bit Business, Dual core 2ghz intel laptop, 4gb RAM, 5600RMP HDD… Are those specs up to stitching RAWs? I was of the opinion that big stitches just took more time due to a lot of use of the scratch HDD, but maybe we’ve just encountered a limitation?

I’ve sent a proper technical support request but they’ve not replied yet.

Cheers,

Adam
CC
Chris_Cox
Feb 14, 2009
No settings that I know of. Photomerge, nor the layers version in Photoshop care about the source of the files/layers.
LH
Lawrence_Hudetz
Feb 14, 2009
It’s dem pesky extraterrestrials! 😀

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