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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Hot Mirrors/ Ir filters a MUST when shooting w red?

C

cable guy

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Hi this is a repost:

" Hi all, i have been using the tiffen hot mirror and just saw my first case of ghosting/ double reflection on my shoot yesterday. in the end i had to take the filter out and shoot without it.

my q is, if i dont use any IR/ hot mirror filters for all my shoots, will it cause damage to the cam's sensor in the long run?

I have been changing my lenses in bright hot sunlight while the camera is still on, will that affect the sensor as well? or do i hav to shield the mount area from light when i swap lenses?

Thanks in advance for any advice."
 
Yes, IR is a pretty rare thing, lots of ND is one thing that "might" cause it. Keep the hot mirror around and only use it if you see the effects of infrared - purple magenta - especially in black synthetic fabrics.
 
we have 2 from rosco...90 % of the time they are just lying around...but if you need them...the 160 usd are worth every cent
 
Michael Morlan said:
I use my hot mirror with ND6 and above. Sometimes, in low light environments, I just leave it in as the "optical flat."

Michael
Click to expand...

Thanks Guys, for the responses.

"optical flat"? meaning..?

Ps. How abt changing lenses in bright daylight conditions? any harm with so much light hitting the exposed sensor?

Cheers.
 
cable guy said:
Thanks Guys, for the responses.

"optical flat"? meaning..?

Ps. How abt changing lenses in bright daylight conditions? any harm with so much light hitting the exposed sensor?

Cheers.
Click to expand...

As Matthew said, Infrared is not going to hurt your sensor. Don't worry about exposing your sensor to light - that is the point of it! :-)

Optical flat is like a "clear" filter (aka "B-glass") to protect the front of your lens. It is made perfectly flat so as not to distort your image.
 
I've read other threads about this and still hear conflicting views.

Should a combined 1.2NDIR, 1.8NDIR filters and so on be used or is a seperate IR filter suitable with ND .9 and above.

thanks,

Dave
 
cable guy said:
Hi this is a repost:

I have been changing my lenses in bright hot sunlight while the camera is still on, will that affect the sensor as well? or do i hav to shield the mount area from light when i swap lenses?

Thanks in advance for any advice."
Click to expand...

I'd say the bare sensor is safer from light than when the lens is in front of it- that lens focuses and concentrates light onto the sensor rather than the diffuse light that falls unfiltered onto the naked sensor.

Imagine an ant walking across the sidewalk and then placing a magnifying glass between it and the sun.
 
I would say the situation in which you need the hot mirror is very very very rare... even when you stack on filters. I tried to duplicate the problem on primes and the RED 18-50mm and couldn't.
 
facetmedia said:
I would say the situation in which you need the hot mirror is very very very rare... even when you stack on filters. I tried to duplicate the problem on primes and the RED 18-50mm and couldn't.
Click to expand...

This has been my experience too. It is rare indeed. But good to have the filter in your kit in case you need it.
 
Guess will have to minimize my tiffen hot mirror usage then.

Good to hear all these comments. thanks guys.
 
facetmedia said:
I would say the situation in which you need the hot mirror is very very very rare... even when you stack on filters. I tried to duplicate the problem on primes and the RED 18-50mm and couldn't.
Click to expand...

I don't agree at all. It all depends in which light you are shooting. Had a Tiffen hot mirror ND 1.5 at my last shoot. Used it for almost every shot - as the light was to bright and the DoF went away from 2 inches to infinity without.
 
Richard Darge said:
I never use a hot mirror and shoot 1.2 & 1.2+0.9 stacked.
Click to expand...

Hmm. Are you shooting in cold climes? In a Texas summer, if I stacked that much in front of the lens, my RED One would be washed with 7 stops of IR, completely washing out the image. Foliage would be desaturated with purple in the shadows from the excess heat it exudes. Similarly, certain black fabrics would be purple.

I haven't tested that much ND in cold environments.

Michael

264_1227356420.jpg

ND 1.8 without IR filter

264_1227356398.jpg

ND 1.8 with Rosco Trucolor IR
 
No kidding, Michael. I can't imagine not using a hot mirror outdoors in the summer. I had a Tiffen IR+ND (which is on Ebay right now, as a matter of fact), and I assumed it was doing a decent job of clipping the IR. But then, just for kicks, I put my Rosco in front of it and BANG. . . I suddenly realized what I had been missing/getting. The foilage just change from a rather sick green to a vibrant one. A HUGE difference. Well, I decided to sell all my Tiffens and buy the Formatt IR+hot mirrors that very day.

Stephen
 
A DP friend of mine called me last week very puzzled because she was testing IR filters on Build 18 to compare to tests she'd done on Build 16. She was stunned to find that there was no difference between using IR and straight ND and she couldn't imagine how a firmware build could ever correct for IR pollution (it can't). It took awhile in the phone call until we realized that the first IR test was done in the heat of a New York summer and the second on a cold New York fall day. IR is essentially heat, so it all wicked off into the air before it could transmit to the camera. She had done all her testing outside in daylight to get the light level needed to use all that ND. Abel does all of its testing indoors at our facility under controlled conditions, so we can best judge the differing performance of filter brands and types.
 
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