EF-S lenses for Scarlet? Issues?

[John O'Brien]

I currently have a Canon XSi and was looking to buy another lens. I was hoping I could also use this lens on the Scarlet with a Canon mount. The Xsi can hold both an EF and EF-S lens. I know that the EF-S lenses are not compatible on all Canon cameras and the element could collide with the camera, does anyone foresee this same issue with the Scarlet?

Also in regards to the EF-S lenses is does the design of the EF-S lens help eliminate the crop factor of 2/3 chip? Are there any other issues to the image that an EF-S lens would create?

Any help would be appreciated. It's basically a cost issue, but in the long haul I would rather spend extra dough on an EF lens if it will be compatible with both cameras.

 

[Tom Lowe]

Are you talking specifically about the 2/3" Scarlet, or also about S35 and FF35 Scarlets?

 

[John O'Brien]

I want to get the S35, but most likely will have to start off with the 2/3 and upgrade later. What would be the advantages/disadvantages of EF-S lenses on either?

 

[Casper Warnich]

If you are buying the 2/3 Scarlet, then I think you will get a huge crop factor because the sensor is so much smaller than the one in the Canon. So if you have a 100mm Canon lens it will become something like a 393mm on the Scarlet. That might be a problem for you.

 

[Tom Lowe]

i have no idea if the 2/3 will even have nikon or canon lens mount options.

 

[sbcooler]

Q?

Q?

These are good questions...the Canon Xsi Rebel and the Xti..I believe they are the same sized sensor...which is??? I thought they were close to equivalent to a 2/3" sensor like the scarlet will have? I know the crop factor for the Xsi and Xti Rebel are 1.6 I believe. Now that's 1.6 measured against an S35 or FF35?

Anyway, I would love to know the same question. Can you buy zoom lenses and the like and interchange them on the Scarlet 2/3" with great success or is the previous person right and the sensors are different sizes between the Scarlet and Canon?

I'd love to have a still cam and cinema cam that I can share lenses with.

 

[David Swan]

The crop factor is reletive to 35mm ie 36x24 mm. So it's a bit smaller than the s35 Scarlet, and a fair whack bigger than 2/3" Scarlet.

 

[A. Bastaki]

a 50 mm lens on a
2/3" is 100mm equivalent (almost as big as 16mm film)
1.6 crop is 80mm equivalent. (almost as big as s35 sensor)

 

[Lee Saxon]

Focal lengths stated on EF-S lenses are in 35mm (36x24mm - 43.27mm diagonal) terms. The XSi has a 22.2x14.8mm (26.68mm diagonal) sensor. The S35 Scarlet has a 30x15mm (33.54mm diagonal) sensor. The 2/3" Scarlet has a 10.1x5.35mm (11.43mm diagonal) sensor.

The formula is :

Lens Focal Length * (Diagonal of lens format / Diagonal of new format)

so a 100mm EF-S lens for instance

100 * (43.27/26.68) = 162.2
100 * (43.27/33.54) = 129
100 * (43.27/11.43) = 378.6

gives a field of view of 162mm on the XSi, 129mm on the S35 Scarlet, and 379mm on the 2/3" Scarlet.

 

[sbcooler]

Focal Len compared to Sony Z1u and magnification

Focal Len compared to Sony Z1u and magnification

I have a Sony Z1u that has a 1/3" inch sensor inside (3 of them). Assuming that's about half the length and width of the Scarlet 2/3 that would get me a 5.1mmx2.7mm or about a a 5.7mm Diaganol. That is about a 7.59x multiplier.

So a 100mm EF-S lense in a true 35 mm sensor would be the equivalent of a 759mm lense on my Sony Z1u? Is this approximately correct?

I am really wondering if the SCARLET will have the same approximate magnification for shooting concerts and events as say my Sony Z1u...anyone have an idea?

 

[Lee Saxon]

So a 100mm EF-S lense in a true 35 mm sensor would be the equivalent of a 759mm lense on my Sony Z1u? Is this approximately correct?

No, you got it a little mixed up because I explained poorly.

The 35mm (43.27mm diagonal) format 100mm EF-S lens on a 35mm format sensor would be the equivalent of a 1/3" (6mm diagonal) format 13.9mm lens on the 1/3" format Z1u--

Lens focal length * ( new format diagonal / lens format diagonal )
100*(6/43.27)=13.9

The "759mm" (actually it's 721.1, the 1/3" format diagonal is ~6mm, not 5.7mm) is what you would get if you somehow mounted that 35mm format 100mm EF-S lens on your 1/3" format Z1u--

Lens focal length * ( lens format diagonal / new format diagonal )
100*(43.27/6)=721.1

Hopefully that made sense, I'm no great technical writer.

I am really wondering if the SCARLET will have the same approximate magnification for shooting concerts and events as say my Sony Z1u...anyone have an idea?

First let's look at a direct comparison of the 1/3" format 4.5-54mm lens in the Z1u and 2/3" (11/43mm diagonal) format--

4.5 * (11.43/6) = 8.6
54 * (11.43/6) = 102.9

So to equal the field of view range of your Z1u, you would need a 9-103mm zoom on the 2/3" Scarlet.

Just for fun, here's both in terms of 35mm format--

The 1/3" format 4.5-54mm lens of the Z1u has a field of view equivalent to--

Focal length * (new format diagonal / lens format diagonal)
4.5 * (43.27/6) = 32.4
54mm * (43.27/6) = 389.9

-- a 35mm format 32.5-390mm lens.

The 2/3" (11.43mm diagonal) format 6.5mm, 8mm, 16mm, 25mm, 50mm, and 75mm lenses for the 2/3" Scarlet have fields of view equivalent to--

6.5 * (43.27/11.43) = 24.6
8 * (43.27/11.43) = 30.3
16 * (43.27/11.43) = 60.6
25 * (43.27/11.43) = 94.6
50 * (43.27/11.43) = 189.3
75 * (43.27/11.43) = 283.9

-- 35mm format 25mm, 30mm, 60mm, 95mm, 190mm, and 285mm lenses.

 

[sbcooler]

Thanks very much. I understand your description much better now. So it seems to me that the Scarlet will have (35FF equivalent) of around 393mm and the Fixed Scarlet will have 224mm....now if Red sells a telephoto doubler, that would get us 448mm...or about 12% more zoom than my current Sony Z1u at maximum zoom.

The reason I was asking this is for shooting concerts where I am quite a distance from the stage at times.

One last thing..if I get 12% more zoom assuming there is a doubler I can put on the Scarlet...since it's a 3K sensor....if I compare that to HDV (1440 x 1080), then I assume I can digitally zoom another 70-80% or so and get a LOWER resolution image, yet one that compares similarly in resolution to HDV but with far greater dynamic range and control. This would be equivalent to having a Z1u with a doubler more or less. Something in the range of 720mm roughly. That should give me enough zoom for most of what I do.

If I want more optical zoom I suppose I could buy the Scarlet where I'd get an interchangeable lense and one that can do some zoom. Any idea of what would be available for something like this and would that be limited to 8x or do lenses get rated at 6x,10x, 12x, etc...Just curious to what options I'd have.

Thx again-

Thanks again

 

[John O'Brien]

Wide angle for 2/3"?

Wide angle for 2/3"?

The 2/3" (11.43mm diagonal) format 6.5mm, 8mm, 16mm, 25mm, 50mm, and 75mm lenses for the 2/3" Scarlet have fields of view equivalent to--

6.5 * (43.27/11.43) = 24.6
8 * (43.27/11.43) = 30.3
16 * (43.27/11.43) = 60.6
25 * (43.27/11.43) = 94.6
50 * (43.27/11.43) = 189.3
75 * (43.27/11.43) = 283.9

-- 35mm format 25mm, 30mm, 60mm, 95mm, 190mm, and 285mm lenses.

That's interesting; it basically seems in order to get a somewhat normal Field of View for the Scarlet 2/3" sensor you need to get the Mini Primes. Is there any other lens on the market that has such a small focal length with out being "fisheye"? The Canon 10-22mm ends up being 38mm at its widest, will a wide angle lens be impossible for the 2/3"?

With these numbers it seems that the camera is going to have to be far away to get wide shots, with a 6.5mm Red Mini Prime how far away would the camera have to be to get the equivalent wide shot on a fully wide 16mm lens on the S35?

I know this question may annoy, but I don't know the formula and information like this may help in a decision to hold off on the 2/3" and wait until I can afford the S35.

 

[Lee Saxon]

That's interesting; it basically seems in order to get a somewhat normal Field of View for the Scarlet 2/3" sensor you need to get the Mini Primes. Is there any other lens on the market that has such a small focal length with out being "fisheye"? The Canon 10-22mm ends up being 38mm at its widest, will a wide angle lens be impossible for the 2/3"?

The large focal length multiplier is because 35mm lenses are designed for a much much larger frame than the 2/3" Scarlet (36x24mm film frame vs 10.1x5.35mm sensor). You need something designed for a much smaller frame. Standard S16 is only slightly larger than the 2/3" Scarlet sensor (12.5x7.41 vs 10.1x5.35) so the focal length multiplier will be less extreme (1.28 times the stated focal length vs 3.78 times the stated focal length with 35mm lenses).

By the way, about that Canon 10mm, you can't get that wide on a sensor this small even with the Mini Primes. You'd need a ~2.6mm Mini Prime to match that field of view. Theoretically they could probably build one but if they wanted it to have acceptable levels of corner sharpness for 3K and not have so much barrel distortion it was essentially a fisheye, the front element would be wider than the camera and cost obscene amounts to make, like this lens :

http://kenrockwell.com/nikon/13mm.htm

With these numbers it seems that the camera is going to have to be far away to get wide shots, with a 6.5mm Red Mini Prime how far away would the camera have to be to get the equivalent wide shot on a fully wide 16mm lens on the S35?

It's difficult to give you an accurate answer.

My Scarlet-to-35mm calculations you quoted assumed that the Mini Prime focal lengths were accurate because they're designed and marked exactly for the 2/3" Scarlet's sensor size.
But if they're in standard S16 film format they would look slightly longer, --

6.5*(14.55/11.43)=8.3
8*(14.55/11.43)=10.2
16*(14.55/11.43)=20.4
25*(14.55/11.43)=31.8
50*(14.55/11.43)=63.6
75*(14.55/11.43)=95.5

-- on the 2/3" Scarlet since its sensor is a bit smaller than S16 format.

The same issues apply to the S35 Scarlet.

However, I can give you a general of how they compare.

Hypothetically if the 16mm lens you mentioned was exactly S35-Scarlet-sized (and the Mini Primes were exactly 2/3-Scarlet-sized) it would be equivalent to --

Focal length * ( diameter of S35 Scarlet format / diameter of 2/3" Scarlet format )
16mm*(33.54/11.43)=47

-- a 47mm 2/3" Mini Prime

and

Focal length * ( diameter of S35 Scarlet format / diameter of 35mm film format )
16mm*(33.54/43.27)=12.4

-- a 12.4mm lens in 35mm format

 

[J.K.Dibbets]

I know that the EF-S lenses are not compatible on all Canon cameras and the element could collide with the camera, does anyone foresee this same issue with the Scarlet?

It hits the mirror array right? I assume scarlet won't have any mirror array...

 

[Wesley Scoggins]

How difficult do you think a "Smart Mount" would be, where you could have auto focus, and internal exposure control?

 

[Lee Saxon]

Exposure control wouldn't require that "smart" of a mount, simply a software feature in the camera that lets you key in the focal length and maximum aperture of the lens you're using (this is how the latest DSLRs allow you to mount 30-year-old lenses without CPUs that had previously been incompatible with new cameras for a decade or more). The exceptions would be Mamiya lenses and Nikon's new G-type lenses, which don't have a physical aperture ring; there would have to be an electronic interface in the mount to allow you to set the aperture on-camera.

Autofocus is more complicated. Assuming the camera has an autofocus sensor, an electronic interface could be placed in a "smart" mount to communicate with the internal focusing motors of new, higher-end lenses. Older lenses that don't have internal focusing would require the camera to have a screw-drive focusing motor and have physical gearing in the mount to connect with it. Performance would likely be unimpressive.

 

[Wesley Scoggins]

Well for the lens without a manual exposure dial on the lens, having an electrical interface into the Scarlet would be necessary to mount an EF lens right?

 

[Lee Saxon]

Yes, add the Canon EF lenses to the Mamiya and Nikon G lenses I mentioned as ones which would require some electronic interface because they lack a manual aperture dial.

My bad, I'm not familiar with Canon and I didn't check if they have aperture rings before I posted.

 

[Wesley Scoggins]

Something that I feel would really assist it as being a DSLR-Killer would be a EF adapter, it would be nice if we were all able to take the Lens from our Canon and Nikon DSLR's, and be able to toss them on our Scarlet.