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Scarlet DOF lens question

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Yarek

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Hey guys total Red newb here i was wondering if someone could answer this question- if I get the Scarlet fixed lens version when it comes out how will that compare in terms of DOF to something like a nikon D90 (still image sensor) or hvx (1/3" ccds)? Im trying to stay as small and light as possible so it could be handheld like a still cam or if using a tripod not to look like a production cam and get much attention. I still would like shallow DOF, not necessarily razor shallow but i assume the fixed lens version + a 35mm adapter+lens will be quite larger than a dslr. To get shallow DOF do I need to spend more and get something like the interchangeable lens version? In that case could I use my existing Nikon primes with some sort of adapter or would I lose features of a lens made for the Scarlet specifically? I assume not really in terms of focus and aperture for motion since they would be set to manual but only if I used the Red for stills? Or am I missing something and thats not the way to go? I think if I read correctly the Red lenses would be very expensive and I might be better off financially with the fixed lens version financially but it all depends on what sort of DOF I could get with that one. Any ideas?
 
Generally speaking the DOF will be greater than the D90 and less than the hvx, but we won't know its precise capabilities until the details on the lens are released, but I'd guess it'll have a maximum f number of 2.8, so you should be able to get it fairly shallow, and then you can of course just stop it down almost as much as you want.

You of course won't have quite the flexibility you'd get with a set of primes on the non fixed version, but I doubt you'd be crippled.

Again this is all speculation until we have confirmed lens details.
 
thanks, so to get true SLR DOF i could try my nikon primes with the non fixed version, but from what im seeing that would be a bad idea considering the crop factor (is there a workaround?) and no AF under any circumstances (for those times you might need it) even with AF nikon lenses?
 
Yarek said:
thanks, so to get true SLR DOF i could try my nikon primes with the non fixed version, but from what im seeing that would be a bad idea considering the crop factor (is there a workaround?) and no AF under any circumstances (for those times you might need it) even with AF nikon lenses?
Click to expand...

You won't be able to get 35mm DOF with the same lenses, precisely because of the crop factor, it just can't be done. In order to get the shallowest DOF you're going to want some really fast lenses. From what's been said so far the mini-prime set will likely cater to this need with some reasonable affordability, but it will mean that you'd be spending substantially on top of the brain itself, and with that kind of expense, it may be your best bet to use your current glass and get an S35 brain.

This is of course, only if you find that a DOF approaching 35mm is necessary for your purposes. You may find the the DOF of the 2/3 fixed, or the interchangeable with your current glass to be perfectly adequate for you.
 
Kenneth Elkington said:
Generally speaking the DOF will be greater than the D90 and less than the hvx, but we won't know its precise capabilities until the details on the lens are released, but I'd guess it'll have a maximum f number of 2.8, so you should be able to get it fairly shallow, and then you can of course just stop it down almost as much as you want.
Click to expand...
No. This is wrong. The smaller the sensor, the greater the depth of field. The D90 has a sensor almost as large as S35, whilst the HVX has a small 1/3 inch one.

If you want to use your Nikon lenses without a crop factor get the Scarlet FF35 brain.
 
Ok im a little lost, i didnt realize the crop factor affected the DOF just cropped the image making lets say an 85mm slr lens something totally different. I do have a bunch of relatively fast nikon primes such as 24mm, 50, 85, 135 in 1.2-2.8. I think id rather have an interchangeable system like a dslr coming from fixed cameras and adapters, so i really need to read into the crop issue etc. Pretty sure i wont go into the S35 price range (or FF35, lol).

If anyone has links to some 2/3" films with info on lenses used or leaked footage that would be great.
 
The smaller the sensor, the greater the DOF. The larger the sensor, the smaller DOF. (edit: this is true for equivalent field of views)

An F-Stop is still an F-Stop, but the 'perceived' DOF changes on different sized formats.

With the fast miniRED primes, it will be possible to obtain shallow DOF at a variety of common focal lengths, but if you want to use your Nikon primes and pricing is an issue, you are better off sticking to another more affordable DSMC system.
---

Edited to add 'perceived', so that I do not confuse the Perceived DOF from the Actual DOF. As sensor size does not change the actual measurements of your DOF when changing one lens to another system, just the practical appearance since the image is cropped in a smaller sensor, thus leaving you with less of the desired shallow DOF in certain shooting situations. Not to say you can not achieve the shallow DOF with small sensors though, just the larger the sensor, the easier it is to obtain shallow DOF. This is what I was trying to apply by stating that an F-stop is an F-stop. Sorry for the miss-communication.

But with an equivalent field of view of a FF 35 mm camera, the 2/3'' scarlet will have about 3.9x more the DOF. Which is still plenty, imo.
 
Yarek said:
Ok im a little lost, i didnt realize the crop factor affected the DOF just cropped the image making lets say an 85mm slr lens something totally different.
Click to expand...

This is a discussion that confused me a lot when I first got to this board too. I finally figured out that people were just looking at this in a totally different way than me.

I was thinking in terms of the SAME LENS, like you.

You're right, the crop factor does not alter depth of field of a lens. That 85mm Nikon for instance would have the same depth of field mounted on a 2/3" Scarlet as it would mounted on an APS (which is coincidentally similar in size to S35, btw) Nikon D90 or even 'FF35' Nikon D3.

What they're saying is that because of that crop factor, you're going to want to use a DIFFERENT LENS on your 2/3" Scarlet to get the same field of view as an 85mm on a Nikon D3. This would be a lens with a far shorter focal length and, therefore, deeper depth of field.

Yarek said:
I do have a bunch of relatively fast nikon primes such as 24mm, 50, 85, 135 in 1.2-2.8. I think id rather have an interchangeable system like a dslr coming from fixed cameras and adapters, so i really need to read into the crop issue etc. Pretty sure i wont go into the S35 price range (or FF35, lol).
Click to expand...

If you're on a tight enough budget that you can't even consider the S35 Scarlet and you have a pre-existing stable of lenses, you might think about getting the interchangeable-lens 2/3" Scarlet. If you don't have to buy lenses, that system would be cheaper than the Fixed lens 2/3" Scarlet. Unless the "$750 more for a complete system" deal is exclusive to the Fixed Lens Scarlet and accessories like power, viewfinder, etc are more expensive on the other models. But I feel like Jim wouldn't do that to us.

Though keep in mind because of the huge crop factor those lenses will be much longer focal length (or more accurately, just narrower field of view) than when mounted on your Nikon.
 
Steven Swigart said:
The smaller the sensor, the greater the DOF. The larger the sensor, the smaller the DOF.

An F-Stop is still an F-Stop, but the DOF changes on different sized formats.

With the fast miniRED primes, it will be possible to obtain shallow DOF at a variety of common focal lengths, but if you want to use your Nikon primes and pricing is an issue, you are better off sticking to another more affordable DSMC system.
Click to expand...

DOF (DEPTH OF FIELD) DOES NOT CHANGE WITH SENSOR SIZE.

The three factors that affect DOF are focal length, F/T stop and the distance from the lens to the object.

What does change amongst formats (Sensor size) is the FOV (Field of View) in other words how wide or tight your frame is.

This ofcourse is taking into account that you are using the same lens across all formats (Let's say a 50mm focal length T2 Cooke lens that covers a S35mm frame) There would be a crop factor involved depending on your format (For instance an S35 Cooke 50mm would be more like a 100mm in 2K or S16mm due to the 2x crop factor)

The FOV (OR how tight the frame is) would be narrower but the DOF (Depth of field) unchanged.

The perceived DOF may be affected due to the tighter frame, but all in all it would be just as shallow or deep across both an S35 4K RED frame or an S16 2K RED frame.
 
To my understanding: There is a change in DOF with a smaller sensor. Just try and visualize it for a moment.

If you crop a picture that was taken with a FF sensor the DOF will appear greater, this is essentially the same effect that you get with a smaller sensor.

Maybe this is just "Perceived", but in a practical sense, that's what we are talking about here for the OP.
 
Steven Swigart said:
To my understanding: There is a change in DOF with a smaller sensor. Just try and visualize it for a moment.

If you crop a picture that was taken with a FF sensor the DOF will appear greater, this is essentially the same effect that you get with a smaller sensor.

Maybe this is just "Perceived", but in a practical sense, that's what we are talking about here for the OP.
Click to expand...

Perceived yes, but optically or from a technical standpoint no.
 
I think people get confused between focal length, depth of field and field of view.

Basically...

Think of a cinema where a movie is projected on to a screen 50ft wide, if you go and pin your bed sheet to the middle of the screen it will only reflect part of the image - the whole screen represents the larger RED sensor and the bed sheet is the smaller HVX sensor. They'll have the exact same depth of field, because they are the same shot, but they will have different field of view, due to the crop factor.

So, all things being equal:

If you sat a RED One next to an HVX200 and framed the exact same shot in both cameras, ie the same field of view, and shot them at the same f/stop, the HVX will have deeper/greater depth of field and the RED will have shallower/shorter depth of field because the RED has a larger sensor.

However, to maintain the same field of view you would have to use lenses with different focal lengths - much shorter (smaller number in mm) on the HVX.

With the same focal length lens on both cameras you would have to change the camera to subject distance, ie move the HVX further away from the scene, to maintain the same field of view. In practice moving back is not always possible or indeed desirable as the scene can appear optically compressed due to the added focal length.

There are a number of factors that affect a cameras ability to capture images with shallow depth of field, sensor size is probably the most important.

Someone will hopefully chime in with a more eloquent explanation, but I hope that helps.
 
Alexander Nikishin said:
Perceived yes, but optically or from a technical standpoint no.
Click to expand...

Sorry for not being more clear. But with an equivalent field a view the scarlet 2/3'' will have around 3.9x's more DOF than a 35mm camera, if I'm not mistaken. I updated my previous post to try and be more clear. Although you are correct that technically the DOF does not change optically if a lenses is put on a different format, but the FOV changes, and thus the perceived DOF changes. Which is what I was trying to clarify.

http://photo.net/learn/optics/dofdigital/

Thanks, LH for the clarification. :thumbsup:

But back to the OP's point, a 50 mm lens on the 2/3'' scarlet would be quite the tele, with less perceived DOF do to a great change in FOV...

--

edit: to repeat myself though, this does not mean the 2/3'' scarlet is not capable of achieving shallow DOF, as we already know.
 
thanks guys for that thorough analysis, so to sum it all up, a 50mm nikon that i have might turn into something like a 15mm on the scarlet, which will make the DOF deeper than on a dslr...right so far? I was confused about the focal length of the lens determining the DOF since within one camera system a 2.8 F stop is always called a 2.8, but I think I know what you mean- with a 300mm lens you see a shallow DOF at 2.8 while with a 24mm it is deep, just like on a zoomed in HVX compared to a zoomed out one.
 
Yarek said:
thanks guys for that thorough analysis, so to sum it all up, a 50mm nikon that i have might turn into something like a 15mm on the scarlet, which will make the DOF deeper than on a dslr...right so far? I was confused about the focal length of the lens determining the DOF since within one camera system a 2.8 F stop is always called a 2.8, but I think I know what you mean- with a 300mm lens you see a shallow DOF at 2.8 while with a 24mm it is deep, just like on a zoomed in HVX compared to a zoomed out one.
Click to expand...

No, a 50 mm nikon on a 2/3'' sensor would have an equivalent field of view of around as a 195 mm lens on a full frame 35 mm camera. Which would give an apparent deeper DOF, just because your cropping the picture with a smaller sensor. But technically the DOF would remain exactly the same, but FOV would be greatly different.

But to obtain the same field of view, as a 50 mm lens on a FF 35 mm camera (which is called 'normal') you would have to use around a 13 mm lens on a 2/3'' sensor and would have around 3.9 times more the DOF. Which means achieving a shallow DOF on a smaller sensor can prove to be more difficult.

Edit:
But you are right that the more narrow the field of view, the more shallow one can make the apparent DOF in its relative system.

What I meant about an 'F-stop is an F-stop', is that it's just a mathematical equation, and does not change from moving a lens to another sized sensor.

Hope this makes more sense. Read the article I posted above, it helps explain more.
 
CC of Benjamin Button was shot on 2/3" Viper camera so now you can compare if its inaf for you
 
I know this topic is very confusing for first-timers.

So let's look at this way:

We have two sensors, one is 2/3" and the other is S35 sized (much bigger).

Sensor size does not change the DOF, an 85mm lens is always an 85mm lens, but sensor size sees it in different ways and here's why: http://en.wikipedia.org/wiki/Crop_factor

But to achieve the same field of view on both you need different focal lengths.

To achieve a FOV of 27º in the 2/3" you need a 20mm lens and on S35 you need a 50mm lens.

The wider the focal length the more DOF (more things in focus) your image appears to have.

DOF is a tricky business, there's a lot about Circle of Confusion and stuff that I never really got into...

But the focal length in relation to the sensor size is the most important factor.

And here's a good table of FOV/Focal Length:
 
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