"Tiles" and depth ...

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Yawns
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Joined: Sun Dec 20, 2015 9:18 am
Location: Benavente, Portugal

"Tiles" and depth ...

Post by Yawns »

Since I got the micro 4/3 camera I'm having a "problem" with the small sensor .. normal subjects (flies, wasps..) don't fit even at low magnification like 4X .. anything bigger than 4mm will not fit entirely.. even the head of a common fly is tricky to fit on a micro 4/3 with a Lomo 3,7x

So many times i have to do 2-3 tiles and later stitch to have things correctly frames...

As I don't have experience with stack & stitch my simple question is this ... should I use always use the same number of frames ....the same START and END point or every tile?..

"Logic" tells me to do so.. apparently all the tiles will have the same variation in perspective and magnification ...

Although is tempting to "shortcut"t as some tiles will require a much smaller number of photos ( the head for example) than others (the wings) and the difference can be very significant.

ImageScreenshot 2019-11-02 at 16.43.38 by antonio caseiro, on Flickr
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rjlittlefield
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Post by rjlittlefield »

If you're using a lens where there is variation in perspective and magnification, then you're pretty much guaranteed to be getting parallax errors, so that might not be the best choice to begin with.

But if you decide to live with parallax errors, then I think the best approach is to (A) be sure that your stitching process allows for changes in scale between tiles, and (B) shoot the minimum number of frames in each stack. If you shoot lots of OOF stuff at the beginning or end of any stack, then you'll be asking the stacking software to align nothing but blur, and that's not a reliable process either.

Different stitching packages have different ways of allowing for changes in scale. It may be called something like "use individual lens parameters for each image".

--Rik

Yawns
Posts: 398
Joined: Sun Dec 20, 2015 9:18 am
Location: Benavente, Portugal

Post by Yawns »

rjlittlefield wrote:If you're using a lens where there is variation in perspective and magnification, then you're pretty much guaranteed to be getting parallax errors, so that might not be the best choice to begin with.

But if you decide to live with parallax errors, then I think the best approach is to (A) be sure that your stitching process allows for changes in scale between tiles, and (B) shoot the minimum number of frames in each stack. If you shoot lots of OOF stuff at the beginning or end of any stack, then you'll be asking the stacking software to align nothing but blur, and that's not a reliable process either.

Different stitching packages have different ways of allowing for changes in scale. It may be called something like "use individual lens parameters for each image".

--Rik
Thank you Rick for spending your time answering ... now I understand ...
I know this is not the best solution and I know that a telecentric lens would be desirable ...

I don't want to do Stack & Stitch .. but Oly m4/3 sometimes forces me do it.
I don't even have specific software for this purpose .. I just use Affinity Photo's "panorama" function ...

I'm in the market looking for a well used and dated camera with a larger sensor APS-C (or possibly FF), like Sony A6000 or Sony A7 (first model) .. it's just for this purpose ... just to screw to the Rig and never get out of there ... as long as the sensor is decent and the shutter is electronic, I don't need any other features ... I think I can get something for 200 euros ... it's the easiest solution.
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elf
Posts: 1393
Joined: Sun Nov 18, 2007 12:10 pm

Post by elf »

I try to use the same start position for each stack as I think this helps keep the perspective the same. My rig is designed for spherical panoramas which helps keep the perspective the same from frame to frame. Orthographic stitching will always have parallax errors unless the lens is telecentric.

Microsoft ICE is still available and free to do the stitching.

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