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Old April 27th 18, 03:11 AM posted to rec.photo.digital
PeterN[_7_]
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Posts: 1,161
Default Funky IR Artefact

On 4/24/2018 12:16 PM, android wrote:
On 2018-04-23 17:29:56 +0000, PeterN said:

On 4/23/2018 1:34 AM, android wrote:
On 2018-04-22 18:53:51 +0000, RichA said:

On Sunday, 22 April 2018 05:40:30 UTC-4, androidÂ* wrote:
Trée arty but... WTF is it???

https://dl.dropboxusercontent.com/s/mjfnh2d0s1wulli/i180422%2311638.jpg


For the record: I used a IR filter on a unconverted EOS M with high
ISO settings. Hard to work without an OVF, witch I have...
--
teleportation kills

I tend to use a Leica viewfinder in the hotshoe, a wide angle lens
set to f/8 so proximity focus is easy.Â* A mild IR filter (cutoff,
around 800nm on a camera with its IR filter removed can easily be
handheld in daylight or even overcast, but a deep IR cutoff
(1000+nm) means using a tripod.Â* A camera with the IR sensor filter
in-place is a pain, cutting out so much of the IR than any exposures
with an IR filter over the lens means seconds of time.

I've got a 760nm totally black filter, so there is an overlapping gap
between the high end of the visible spectrum and low end of the IR
one and that can be used at high ISOs sunny days. If you got steady
hands, there is another example from a few years ago in the gallery
on my blog.

https://wp.me/P3strj-7Y

I've gotten it down to where I can convert an old Nikon D70 (the
easiest camera to convert) in 15 minutes.

I might just pull the the filter stack out of the EOS M eventually.
Can't be that difficult...


You might lose autofocuse. The near IR light has a different wavelength.


On a mirrorless? Don't think soo...


You may be right. I had the IR filter pulled on my P&S, and did not lose
autofocus. It may depend on the size of your sensor. According to
articles I've read, you lose AF if you try that on a full frame.

--
PeterN