Fisheye to Rectilinear using Lumix G 8/3.5

akulya

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Jun 21, 2010
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249
Hello,

Firstly, please give credit to our fellow forum member Miles for taking and sharing the first pictures using this lens on this site (here)

I have used photoshop cs3 v.10 for windows, and the excellent (and free!) Panorama Tools plugin, although, I am by no means an expert user of either.

This is a bit of a rough and ready, using a 200K Jpeg as a starting point, but I think it shows a little promise - showcasing the potential to use the fisheye as a UWA prime.

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I have cropped fairly hard, and without really knowing subject distance I cannot make a good guess at what the equivalent focal length might be after correction.

With a raw file, and a more attenuated process (which will come in time) I would expect at the very least a mediocre improvement in FOV. (i.e something like 20mm FF equiv.)

If Miles would like to upload something RAW for the community to experiment with; I am sure there would be some smiling faces
 

Narnian

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Aug 6, 2010
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Richard Elliott
Thanks! This definitely shows how a limited use lens can be brought into the general use fold. I look forward to the experiments.
 

Gwendal

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Jun 6, 2010
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300
Thanks Akulya ! Very interesting - this would confirm that indeed the fisheye really is a specialty item...
 

akulya

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Jun 21, 2010
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249
Oh it's a speciality lens yes,

My thinking was - I will only rarely use a UWA lens, and equally only rarely use a fisheye; but want a high quality lens that has a ~16mm FF FOV, (specifically, one wider than the 9-18 m.zuiko) on those rare occasions I do; will this fisheye fit the bill?

I know the 7-14 is the natural lens of choice, but it is frankly out of my budget, and although I'm not really into miniturisation for the sake of it, the 8mm is lots smaller and more affordable.

Lenses at this FL will always be speciality, but the idea of getting one UWA lens for both rectilinear and fisheye uses appeals to me - IF the FOV is still wide enough after distortion correction; and this is still uncertain.
 

Gwendal

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Jun 6, 2010
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The 7-14 seems to be around €1000 vs this fisheye €800 - at this price level, isn't it more interesting to go the extra mile ? (interestingly, the page I consulted mentions that the 7-14 is the ideal lens for "taking pictures of your friends" - wonder what they had in mind). And indeed, there is the matter of the actual FOV after necessary corrections, as you mention... even if indeed the size of the fisheye is quite reduced. Anyway, both out of my sights... at least for now ;-)
 

akulya

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Joined
Jun 21, 2010
Messages
249
Nice one Miles,

I'm still very much playing with settings until something nice happens but I have tried a couple more using your raw as an original. Sadly it seems that photoshop doesn't like intensive floating point editing with 16bit tiffs (who knew?), so these are max res jpegs from 8bitters.

Firstly - your original shot
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I straightened it according to the vertical crease in the brickwork, cropped it lightly at the edges, and then ran it through a panotools conversion with the HFOV set at 150° (arrived at via trial and error).

This gives you an image that is distortion corrected, but border distorted...

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[edit] this red square image was knocked up afterwards, just to illustrate the distortion, and was not used to create the pics below [/edit]

A constrained 4/3 crop of the centre gives you
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An unconstrained "by eye" crop of as much as looks alright (v.subjective obviously) would give something like
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I have my working tiffs zipped here if anyone is interested (they're the same as the above jpegs, but bigger)

I hope people are finding these experiments amusing!
 

PeterB666

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Jan 14, 2010
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Very interesting. Certainly a lot of the shot is discarded.

I would like to see the original of the first image too if you can post it.
 

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