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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 :)

Scarlet wide...

Thanks Haakon, that all makes sense now. It what I supposed was true but I just needed confirmation.

I'll file the teleconvertor bit in a wish list thread as its going to get lost in here and only Red can really answer that one.
 
Wiyum said:
Well, they're really both important. Think of it this way: use T-stops when talking to your gaffer; use F-stops when talking to your first AC. While T-stops take into account light loss due to the lens elements etc, the actual optics dictate focus, so you need to use F-stops when determining depth of field and other focus concerns.

From a practical perspective though, I've yet to see a lens where the two differed by enough that it should have made much of a difference. The couple tenths of a stop less in exposure won't kill you if you're using F-stops for exposure, and if depth of field is so narrow that the difference creates problems because you calculated depth of field using T-stops, then you probably shouldn't be shooting as wide open/telephoto/close to the subject as you are.
Click to expand...

They don't differ - actual f-stop can match T-stop. In fact (what has been missing here) the reality is that T-stop IS THE LIMITING FACTOR for f-stop. You can only open Your aperture as wide as the T-stop of the lens allows You, but You can then close it down (further limit the amount of light hitting the sensor) for what ever reason... The f-stop is kind of override for T-stop, but You can't "ADD" light by opening the aperture beyond the T-stop of the lens...
 
Alsone said:
Thanks Haakon, that all makes sense now. It what I supposed was true but I just needed confirmation.

I'll file the teleconvertor bit in a wish list thread as its going to get lost in here and only Red can really answer that one.
Click to expand...

You don't have to - Jim said YES to question about both the wide-angle and tele-photo adapters. The same way they are listening to the ones who wants to go "fishing", they are also listening to the ones who wants to see the moon. I actually believe that there is more people wanting tele-photo then wide-angle - we will see from the sales in late 2009...

Go and start saving! I'm doing the same...
 
Impagliazzo said:
Ok, but when you guys say T2.8 are you strictly referring to the T-stop or does it men the F-stop is going to be F2.8 as well?

Please enlight me.
Click to expand...
Here's a nice definition: http://en.wikipedia.org/wiki/F-number#T-stops

On cinema lenses, the numbers on the iris dial are typically T-stops, which are a little higher number than the F-stop. Scarlet is (currently:tongue:) T2.8, which is probably about F2.5.
 
Everyone wants telephoto, but wide angle is harder to do well with adapters.

Everyone wants telephoto, but wide angle is harder to do well with adapters.

Peter Majtan said:
You don't have to - Jim said YES to question about both the wide-angle and tele-photo adapters. The same way they are listening to the ones who wants to go "fishing", they are also listening to the ones who wants to see the moon. I actually believe that there is more people wanting tele-photo then wide-angle - we will see from the sales in late 2009...

Go and start saving! I'm doing the same...
Click to expand...

Everyone wants telephoto, but wide angle is harder to do well with adapters, telephoto is pretty easy to do well with adapters. That is why we are pushing to have the base lens as wide as possible.
 
AquaVideoRed206 said:
Everyone wants telephoto, but wide angle is harder to do well with adapters, telephoto is pretty easy to do well with adapters. That is why we are pushing to have the base lens as wide as possible.
Click to expand...

I agree completely - that's what this thread is all about. I was just addressing Alonso's question about the tele-photo adapter.

You can bet I'm getting both the WA & the TP with every one of the (at least) 5 Scarlets we are going to buy. I hope RED offers some sort of discounted "production package" with Scarlet, both WA & TP, basic rail system with matte box, few batteries (or RED-BRICK external solution) and few CF cards... :innocent:
 
Chris Newman said:
Here's a nice definition: http://en.wikipedia.org/wiki/F-number#T-stops

On cinema lenses, the numbers on the iris dial are typically T-stops, which are a little higher number than the F-stop. Scarlet is (currently:tongue:) T2.8, which is probably about F2.5.
Click to expand...

Chris how can a lens with T2.8 allow You to open the aperture to f/2.5 (wider then 2.8)? Either there is something wrong with Your assumption, or I am lacking some knowledge in this area. Please enlighten me...

PS: Scarlet is not going to be "cinema-style" lens T-stop numbering I guess. It should by all means have an internal metering system that reports to You with actual aperture controlling the amount of light hitting the sensor, but I could be wrong. It just does not go well with the "mass-adoption" strategy...
 
F numbers doesn't count in the fact that lenses block light even if they were at the impossible 0.0 in aparture. Meaning, the lens itself blocks out light and because T-stops measure the actual light coming through it counts in that light reduction.
So therefor T-stops are generally a little higher then F-stops.
I believe that the F-stop for Scarlet would be about 2.0 or around that number. (or is that wrong? I thought about a T-lens that had the number of 3.0 and was like 2.0 or something in F-stops)
 
Unless I am completely wrong "higher" here does not translate to "higher" numbers. For example one would "open-UP" aperture "down" to 2.0 from 8.0 if You know what I mean. Counting in that sensors are not 100% light efficient, then the actual f-stop should be "lower" from 2.8 to about 3.0 - I don't see how when lens lets through light with T-2.8 loss how could we gain "more" light with f-stop "up" to 2.5...

Please someone correct me if I am wrong...
 
Because the T-stop messure light traveled through the lens = Transmission -stop
F-stop = Focal ratio = The diamater of the aparture ring

F is about the aparture while T is about the light...
So, because F isn't about light the aparture can be F2.5 while the actual light coming through points to T3.0.

Which means that if the Scarlet lens has T2.8 then the F-stop is probably lower then that. I don't know how much, someone here said 2.5 but it could be lower...
 
No, Glazarus is right. Since all lenses absorb some quantity of light, the T-number of any given aperture on a lens will always be greater than the f-number. Usually the difference is minimal - it won't more than an entire stop of difference as he suggested, but it can be a few tenths of a point or so. Since DOF can sometimes lie within a single point depending on shooting conditions, knowing the precise T-stop is critical for someone doing calculations requiring aperture information. That's why it's there. :) But the difference is usually not that severe; I believe the RED 18-50mm zoom lens is an f/2.8 lens (but limited to t/3.0 due to transmission properties). Scarlet's lens is probably more like an f/2.6 - but since you can't actually use that extra bit of light (again, the f/stop is just a ratio, not the usable quantifier), it is proper of RED to list the lens as a t/2.8.
 
...yeah and also I said "higher" and meant a "higher number".
You can say higher or lower number. If you say greater and smaller it sounds more like the actual size of the aparture...
anyway, it depends on how you speak about the aparture. Some speak of the size while some in the mathematical term.

...and I like the movie "PI" so :)
 
Peter Majtan said:
In fact (what has been missing here) the reality is that T-stop IS THE LIMITING FACTOR for f-stop. You can only open Your aperture as wide as the T-stop of the lens allows You, but You can then close it down (further limit the amount of light hitting the sensor) for what ever reason... The f-stop is kind of override for T-stop, but You can't "ADD" light by opening the aperture beyond the T-stop of the lens...
Click to expand...

I honestly can't make sense of exactly how you think this works, but follow the links that others have already posted; they will explain F-stops and T-stops effectively.
 
Peter Majtan said:
T-stop IS THE LIMITING FACTOR for f-stop. You can only open Your aperture as wide as the T-stop of the lens allows You, but You can then close it down
Click to expand...
Peter, I think you are mistaken about this. Any given lens typically has T-stops or f-stops. If it is a cinema lens, it usually has T-stops. Wide open it might be T-2.8, but you can close it down to T-5.6, for example. If it is a still or video lens, it usually has f-stops.

Have a look at the Wikipedia page: http://en.wikipedia.org/wiki/F-number#T-stops
 
T-stops and F-stops are two different "stops" based on two different kinds of measurements that is for the same mechanism in the lens...

...that sounds advanced but read it a few times until it doesn't.
 
59xfish said:
Well knowing that just about every action sports film/video maker in the world will buy Scarlet it only makes sense to give them what they will all ask for.
1) An extreme fisheye adaptor
2) A zoom through wide angle adaptor
3) A zoom through 2x tele adaptor.

I can't even imagine how many cameras and said lenses are going to sell to all the skate, surf, snow, dirt bike etc crews worldwide. All I have heard since NAB is Scarlet.
Click to expand...



yeah and all that crappy footage quality from DV or HDV will gone (mostly)
wow what a nice time to watch amazing surfing movements shot on 3K on regular basis in massive scale :w00t:
 
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