Flat Stiching - Overlap ?

[Anders_HK]

Hi,

For flat stitching using a sliding adapter on a 4x5 camera, how much overlap (min %) is required between the images?

Thanks

Regards
Anders

[Jack Flesher]

30% is comfortable, 20% marginally adequate for smooth transitions...

[Carsten W]

30% is comfortable, 20% marginally adequate for smooth transitions...

That's roughly what you need for normal panorama stitching. Wouldn't you need less if you were using a sliding adapter? I mean, theoretically, if you were *really* accurate, you could get away with exactly no overlap and just put the frames next to each other? Or is this to allow for correction of distortion, in which case I guess it would be lens-dependent...

[Jack Flesher]

That's roughly what you need for normal panorama stitching. Wouldn't you need less if you were using a sliding adapter? I mean, theoretically, if you were *really* accurate, you could get away with exactly no overlap and just put the frames next to each other? Or is this to allow for correction of distortion, in which case I guess it would be lens-dependent...

Actually, in regular panorama stitches, 20% is very thin as the software sometimes needs to do a lot of geometric transformation... With a flat stitch, I'm sure you could get away with 10% in most cases, but then why risk it?  

[Anders_HK]

Leaf here in Hong Kong has told me 5mm of sensor. However, that means 15% of short side and 11% of long side.

Does anyone have experience of overlap for flat stitching?

Thanks again.

Regards
Anders

[elf]

Hi,

For flat stitching using a sliding adapter on a 4x5 camera, how much overlap (min %) is required between the images?

Thanks

Regards
Anders

5% is adequate if you're not changing any settings. If you're also doing focus stacking then 10%-15% works.  It may also depend on the stitcher and the output projection.  CS4 won't recognize the images as part of a panorama if the overlap is too small (but it's also easy to align the images manually)

[Jack Flesher]

Leaf here in Hong Kong has told me 5mm of sensor. However, that means 15% of short side and 11% of long side.

Does anyone have experience of overlap for flat stitching?

Thanks again.

Regards
Anders

What concern exactly are you trying to alleviate?  Total capture time? File and/or processing overhead?  At the end of the day, what does it really matter if you end up with one more frame in your stitch because you overlapped 20% instead of 5%?

[Don Libby]

I have always purposely done anywhere between a 30 to40% overlap figuring that it's better to have too many than not enough.  I remember one panorama where I had 8 images but only needed to use 6; of course I didn't know this until I got home (some 2,000 miles later).

I've always taken much more time in setting up the shots than what I actually took in taking them.

Follow Jack's advise, in the end does it really matter so long as you got the image you're after?

Don

[Anders_HK]

What concern exactly are you trying to alleviate?  Total capture time? File and/or processing overhead?  At the end of the day, what does it really matter if you end up with one more frame in your stitch because you overlapped 20% instead of 5%?

Jack and all,

This may be the answer;-

5% is adequate if you're not changing any settings. If you're also doing focus stacking then 10%-15% works.  It may also depend on the stitcher and the output projection.  CS4 won't recognize the images as part of a panorama if the overlap is too small (but it's also easy to align the images manually)

I am simply working on the design of a custom made sliding adapter that will be built for me. I will use it on my 4x5. Thus interested to know what overlap people use when flat stitching. Stitching by panoramic head or similar requires more overlap.

Thanks.

Regards
Anders

[Jack Flesher]

Jack and all,

This may be the answer;-

I am simply working on the design of a custom made sliding adapter that will be built for me. I will use it on my 4x5. Thus interested to know what overlap people use when flat stitching. Stitching by panoramic head or similar requires more overlap.

Okay, got it... You are designing a custom sliding back that has indents at precise pre-determined stitch locations --- I've been there, done that and have the tee-shirt   And FWIW, at the end of the day I found it as convenient to perform the overlaps using the eyeball method -- LOLOL!  And don't forget the requirement will change if you swap to a larger or smaller back.  Anyway, if you are only going to do basic flat stitches, 5% is ample.  However, if you are also going to focus blend, the overlap requirement changes with focal length and for long lenses used form close to distant focus points, even 15% may not be enough -- remember that you need room for the software to generate the blend masks at the overlaps.  

Best of luck,

[Anders_HK]

Okay, got it... You are designing a custom sliding back that has indents at precise pre-determined stitch locations --- I've been there, done that and have the tee-shirt   And FWIW, at the end of the day I found it as convenient to perform the overlaps using the eyeball method -- LOLOL!  And don't forget the requirement will change if you swap to a larger or smaller back.  Anyway, if you are only going to do basic flat stitches, 5% is ample.  However, if you are also going to focus blend, the overlap requirement changes with focal length and for long lenses used form close to distant focus points, even 15% may not be enough -- remember that you need room for the software to generate the blend masks at the overlaps.  

Best of luck,

Jack and all above,

Much thanks for your help. I tried stitching by turning the camera on my panoramic ballhead, dont like it because it does not let me see the whole image for composing. Also it is a spherical capture and not flat.

I like to see the whole image for exact composition. The sliding adapter I work on is aiming at utilizing a 4x5 groundglass and traditional large format lenses. The purpose will be panoramic stitching and at times 2x3 captures. With up to around a 30MP digital back that sounds as should work with sharp traditional large format lenses, for more MP will mean diffraction. Else, yes... simply turning the camera on the tripod would be simpler...

Regards
Anders