Poor stitching using RAW in photomerge

[Adam_B...@adobeforums.com]

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/72157613267634565/>

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.

[George...@adobeforums.com]

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.

[Adam_B...@adobeforums.com]

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!

[Lawrenc...@adobeforums.com]

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.

[Lawrenc...@adobeforums.com]

I see you have tried merge layers. Do a complete flattening instead of merge.

[George...@adobeforums.com]

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?

[Chri...@adobeforums.com]

Adam - where can we find the original, unmerged RAW files to test?

[Adam_B...@adobeforums.com]

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.

[Adam_B...@adobeforums.com]

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

[Chri...@adobeforums.com]

Ok, I've got the files - we'll look into it.

[Chri...@adobeforums.com]

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.

[Adam_B...@adobeforums.com]

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

[Chri...@adobeforums.com]

Yeah, I didn't have a problem with them. So, I'm not sure what you're seeing exactly.

[Adam_B...@adobeforums.com]

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

[Chri...@adobeforums.com]

No settings that I know of. Photomerge, nor the layers version in Photoshop care about the source of the files/layers.

[Lawrenc...@adobeforums.com]

It's dem pesky extraterrestrials! :D