RED lenses - why not T stop

[roryhinds]

There has been a thread in the lens section about the use of F stops over T stops on the RED lenses and I thought RED might not have seen it - thus me posting here.

What's the deal with the F stop on the RED lenses?
Surely it would be better to mark the lenses in T stops like all other Cinema lenses.

The other point being they would then work well in a mixed lens situation so you can easily mix and match your Zeiss with your RED's and Cookes.

What's the reason behind RED marking their lenses in F stops?

[Brook Willard]

This thread in the lens section is a good place to start. :)

[roryhinds]

that was the thread that I was refering to...

and I wanted to see if posting in another section would get any feedback from the RED team

[el_cheapo]

perhaps both the f/stops and t/stops will be marked on the lenses? maybe the massive exposure latitude of mystrium renders light transmission an irrelevant piece of information.... supposedly they were going for 11 1/3 stops, which to me seemed like crazy talk. Then again, a year ago the whole idea of an affordable 4k camera was crazy talk.

Given the size of the sensor, it seems to me that one could shoot their footage the same way they would shoot 35mm stills, disregarrding t/stops altogether

[roryhinds]

and what happens when your on a professional shoot and you have a set of Zeiss lenses they you're using with your RED and you want to change lense but one is in T and the other is in F.

Cinema lenses have T stops, why not RED lenses too?

This has been discussed before - my point was to get feedback from RED.
I don't think RED visit this part of the forum much hense me posting in another section.

[Kevin Halverson]

perhaps both the f/stops and t/stops will be marked on the lenses?

This would be an interesting approach. I for one would be happy with just the t-stop markings, but having both would be fine.

... maybe the massive exposure latitude of mystrium renders light transmission an irrelevant piece of information....

The concept of a t-stop rating normalizes the lens and is always valid information for any situation where more than one lens is used in the same production. No lens has zero transmissive losses, so knowing the quantity of attenuation is a valid piece of information regardless of the speed and latitude of the sensor(s).

[Finner]

I don't think RED visit this part of the forum much hense me posting in another section.

From what I have noticed the RED team goes through most every thread and I would be shocked if they had not checked out the T vs F stop discussion. It has become very clear to me that Jim is not about a trickle technology approach with his products. He is however real big on the trickle down approach with information on his products. Jim knows how to keep the hype up and to do that he kicks out bits of very exciting info every once and a while. Having f-stops on the prototype lenses at NAB would make a lot of sense if you did not want to raise too big of concern with other lense manufacturers at that time. Also when the lenses do start to ship it would be a big announcement to say the lenses have been calibrated in T-stops and then if they tested very high in comparison with high end cine lenses some real big press would come about. I also feel a bunch of other exciting camera tech advances and upgraded features will be announced upon shipping. Jim seems to have been playing his cards by just showing enough of them to keep interest and excitement high, but I suspect there are some big cards he has been keeping close to his chest that will pump up hype huge as the camera begins to ship. This of course is all just speculation but if you take a close look at how things have worked so far it makes a lot of sense.

[Stephen Webb]

I have no doubt that the thread has been read by Red (sorry, can't help it) and they've made a choice not to respond. I'm sure they were asked plenty of times at NAB as well, but no-one got an answer on that.

If I were the cynical type (moi?) I'd suggest that f-stops are being used 'cause that way they appear to compare more favourably with other cine lenses.

But as I'm not, I'd suggest that maybe they just haven't been completed and fully tested yet so t-stops are unknown.

:)

[Brook Willard]

Just to bring Jarred's word in here:

way to take things way off topic Rory.

Our lenses have really accurate F stops, and all of our lenses are calibrated to the sensor and the loss from the front through to the back plane is minimized as much as possible. Your not loosing a full stop between F and T stops like some older lenses.

[Stephen Williams]

Hi,

Can't think of any lenses that are 1 stop between F & T stop. My 30 year old Cooke 20-100 is F2.8 T3.1, thats under 1/3 stop!

Stephen