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Alexa Infrared Issues

Sanjin Jukic

Sanjin Jukic

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Alexa Infrared Issues

If you are still interested in Alexa there is already reported infrared issues.

There is no perfect digital camera I would say...!!!!

"There where also big differences between what we measured with our light meter,
what the camera recorded and what the density if the filters was.

Sometimes there was more than a stop difference between what we measured and
what the filters were supposed to give. LIke the Panchro 1.5 hotmirror,
is suppose to block 5 stops of light be it ony blocked three to four.
When you are depending on your light meter as ARRI recommends, you might be in for a surprise."

Reported by Bastiaan Houtkooper NSC>>>

To compare with MX read more:

RED MX IR Tests: The New Sensor is Similar to the Old Sensor by Art Adams>>>
 
Last edited by a moderator:
Sanjin, thanks for mentioning my article here, not so nice to publish pictures without permission....

To complement your post:
I am clearly stating that people should test themself and use a good waveform on set. The stop difference we noticed has nothing to do with the Alexa.

I am sure sooner or later the Alexa will have build in 'meter' too for now use a waveform and if you are sure about your filters, use a light meter.

Art Adams also wrote a nice article about the issue:
http://provideocoalition.com/index.php/aadams/story/arri_alexa_and_far_red_a_problem_thats_already_been_solved/P0/
Where there is also a quote from ARRI why they choose this solution.

Personally I am happy that the MX has less sensitivity for IR although I also got some complains about the red tones in grading. Even know a company that switched back to film because they could not get their (red) logo right. (not my client so I am not sure how valid this point is)
It is clearly is a complex balance between giving max tonal range and blocking unwanted side effects. With camera's becoming more and more sensitive, this problem is something to look at and it will affect us all.

Indeed there is no perfect camera but both RED MX and ARRI Alexa are a joy to work with and give good results if you know the pitfalls. That means testing and testing. With my site I share experiences like we also do on the mailinglist there and help each other if needed.

Please keep REDuser a positive place too, with respect for other people and other brands.
 
Interesting the Rosco does a poorer job of IR cut than the Panchro on the Alexa. On the Red One tests, they seemed much more comparable.
 
Bastiaan Houtkooper said:
Sanjin, thanks for mentioning my article here, not so nice to publish pictures without permission....

To complement your post:
I am clearly stating that people should test themself and use a good waveform on set. The stop difference we noticed has nothing to do with the Alexa.

I am sure sooner or later the Alexa will have build in 'meter' too for now use a waveform and if you are sure about your filters, use a light meter.

Art Adams also wrote a nice article about the issue:
http://provideocoalition.com/index.php/aadams/story/arri_alexa_and_far_red_a_problem_thats_already_been_solved/P0/
Where there is also a quote from ARRI why they choose this solution.

Personally I am happy that the MX has less sensitivity for IR although I also got some complains about the red tones in grading. Even know a company that switched back to film because they could not get their (red) logo right. (not my client so I am not sure how valid this point is)
It is clearly is a complex balance between giving max tonal range and blocking unwanted side effects. With camera's becoming more and more sensitive, this problem is something to look at and it will affect us all.

Indeed there is no perfect camera but both RED MX and ARRI Alexa are a joy to work with and give good results if you know the pitfalls. That means testing and testing. With my site I share experiences like we also do on the mailinglist there and help each other if needed.

Please keep REDuser a positive place too, with respect for other people and other brands.
Click to expand...

Bastiaan,

thanks for your reply.

btw, I'm sorry but also didn't get a "warning" from your page that is not "allowed" to "transfer" those image links from your test photos here.

Maybe I should ask first but was also thinking that you as a RED user would appreciate this.

I'm for fair and positive presenting all the facts here at the forum that I can get about anything that's could be interesting information for any of RED users.

Keep testing scientific about Alexa, RED1-MX, tomorrow Epic and Scarlet as much as possible and I'll stay tuned on it.
 
How much DR Alexa has in LINEAR mode in 10bit quicktime file ? I don't believe that it has 13.5 stops... I've seen Genesis in linear mode with only 9 stops but in LOG mode it had around 12.5 stops...
 
Thanks for Sharing
 
Sanjin Jukic said:
Bastiaan,

thanks for your reply.

btw, I'm sorry but also didn't get a "warning" from your page that is not "allowed" to "transfer" those image links from your test photos here.

Maybe I should ask first but was also thinking that you as a RED user would appreciate this.

I'm for fair and positive presenting all the facts here at the forum that I can get about anything that's could be interesting information for any of RED users.

Keep testing scientific about Alexa, RED1-MX, tomorrow Epic and Scarlet as much as possible and I'll stay tuned on it.
Click to expand...


Hey Sanjin, you really don't need to put inverted commas randomly around nearly every third word. In fact, as a rule, if you just cut ALL of them, your posts would be easier on the eye.

Hey Sanjin, you really don't need to "put" inverted commas randomly "around" nearly "every" third word. In fact, as a rule, if you just "cut" ALL of them, your "posts" would be easier "on" the eye.

See what I mean?


Yours sincerely,
Ruairi Robinson
Grammar cop.
 
Sanjin, lets have a drink on all good camera's next time we meet, IBC?
I have no problem with a small picture and a link but this was out of proportion.

@victor: We can not discuss the ProRes output yet, for now it is HD output only. Just one advice, which counts for every camera, go to a rental house and test it yourself. Everybody sees images differently and sets different priorities. It never about the math, its all about the image itself.
But let me say this: It gives a very nice image and is able to squeeze a lot of contrast within the REC709 space.
Can't wait to see the same with EPIC HDR. It will make shooting and CC much more comfortable.
 
I happen to love Sanjin's epic use of quotes.
 
Ruairi Robinson said:
Hey Sanjin, you really don't need to put inverted commas randomly around nearly every third word. In fact, as a rule, if you just cut ALL of them, your posts would be easier on the eye.

Hey Sanjin, you really don't need to "put" inverted commas randomly "around" nearly "every" third word. In fact, as a rule, if you just "cut" ALL of them, your "posts" would be easier "on" the eye.

See what I mean?


Yours sincerely,
Ruairi Robinson
Grammar cop.
Click to expand...

Ruairi,

thanks for your kind grammar corrections...

also as you would probably found from before that I like a sort of breaking the rules even if they are all made by a grammar cop...


Tom Lowe said:
I happen to love Sanjin's epic use of quotes.
Click to expand...

Tom,

thanks for your understanding.

It's a pity that I still do not have time and enough financial sources to join your project.

But maybe could be possible in a year for example with Epic on your next project...
 
I think that now the Alexa's out in the wild, a lot of the anti-Red FUD will die off as everyone sees that CMOS cameras tend to behave in a way that is different from film and is different from video and, rather than blaming the camera(s), DoP's need to just learn how to use them.
 
Shane Betts said:
I think that now the Alexa's out in the wild, a lot of the anti-Red FUD will die off as everyone sees that CMOS cameras tend to behave in a way that is different from film and is different from video and, rather than blaming the camera(s), DoP's need to just learn how to use them.
Click to expand...

I think you're pretty much spot on...
 
Shane Betts said:
I think that now the Alexa's out in the wild, a lot of the anti-Red FUD will die off as everyone sees that CMOS cameras tend to behave in a way that is different from film and is different from video and, rather than blaming the camera(s), DoP's need to just learn how to use them.
Click to expand...

Very well said Shane, couldn't agree more! I get rather annoyed and fustrated not to mention shock at how many DOP's don't understand the technology enough and have put the time in to understand it before going on shoots with it.
I rent my camera a lot and some of the questions i get back are baffling, coming from DP's. Not to mention the first and quickest thing they like to do is 'blame the tools' when something is a miss...not the one using it not understanding it properly!
 
Brook Willard said:
I hear digital sucks.
Click to expand...

Yeah. I want everything the way it used to be.

I remember when nonlinear editors first appeared on the scene. Nine out of ten editors said they weren't as good as a Steenbeck/BVE9000 and that they'd never catch on. Most eventually swallowed their words, learned the new technology and never looked back. Some stubbornly stuck to their guns and now they're delivering pizzas.
 
Craig W. Bickerstaff said:
I didn't realize Michael Kahn was delivering Pizza on the side.
Click to expand...

:001_smile: OK, OK, OK. Nine out of ten ordinary working editors. There are those to whom the rules do not apply. Can't a guy talk out his arse without being picked on around here? :rolleyes5:
 
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