Canon/Nikon lenses not usable on Scarlet Cinema?

[J Davis]

tokina 11-16
6mm mini prime,
8mm mini prime

 

[Jeff Kilgroe]

Using FF35 as a reference doesn't make a lot of sense for me -- you're suggesting that the majority of people here primarily shoot FF35 and thus have that range of focal lengths in their head. I shoot 35mm cine / Super-35 / APS-C / digital 35mm (Genesis, Alexa, F35, Red One, Epic, etc.) and have those focal lengths in my head... it takes some work to mentally convert them to FF35 equivalents. Very little filmmaking is done with FF35 formats (Canon 5D and VistaVision mainly) compared to 35mm cine, so why should FF35 be the basis for discussion on typical focal lengths used for filmmaking? FF35 is primarily a still photographer reference.

The main problem is that people in their posts don't label the format they are referring to, that's all, when they say that "this is equal to that..." in terms of equivalent focal lengths, hence the confusion. That and some people don't know that FF35 refers to 36mm x 24mm, and all of this is further confused by the fact that the M-X sensor is larger than Super-35 (30mm wide, not 24mm wide) and yet Red calls it a S35 sensor.

+1000

Not everyone thinks in terms of FF35. I personally don't. Since getting the Nikon D3, I have to re-think lens selections in relation to APS-C/S35/NikonDX terms or in terms of medium format, which is what I tend to use for stills.

I think crop factors are over-used to the point where it has caused mass confusion across the photo and video industries. People don't tend to calculate or use crop factors properly. They always blindly assume that everyone wants to think in FF35 terms, etc..

Any cameraman who has been shooting broadcast SD/HD 1/2" to 2/3" cameras their whole career is not going to think in FF35 terms most of the time, if at all. They know what FOV they get on a 2/3" HDCAM when using a 6mm focal length. Just as a cinematographer who primarily shoots S35 has a good feeling what a 20mm focal length will do for them.

Another peeve of mine... diagonal imager measurements. YOU DON'T NEED THE FRICKIN' DIAGONAL TO CALCULATE A CROP FACTOR, NOR SHOULD YOU USE IT TO CALCULATE THAT CROP FACTOR! Sorry to yell, but there are only two reasons that explain why people would use a diagonal measurement to calculate a linear scale (crop) factor. 1) They failed high-school geometry and don't know any better. 2) They want to over-complicate things to make it seem like they know what they're doing. Either to be a pompous ass or to cover up reason number 1.

Diagonal imager measurements are great for inter-relating sensor areas when aspect ratios differ or to determine your minimum coverage circle needed. If you use a diagonal to calculate a crop factor, then it only works when aspect ratios are the same, and in that case you may as well use a linear side dimension as you will get the same answer without the deriving the diagonal. If the aspect ratios differ, then referencing the diagonals for crop only spawns error and gives you a relational proportion and not a scalar value for crop. Crops factors should always be linear references to your dominant, typically horizontal, dimension. If the aspect ratios are the same between compared frame sizes, then primary dimension is irrelevant. Ad David Mullen says, one should always reference what they are relating to. Many of us are accustomed to assuming FF35 comparison because that's just what the culture has devolved into over the past few years. However, with the multitude of new formats, even within the same camera system in many cases now, we really need to identify our frame of reference.

Another thing that I see pop up in this thread and countless other places. LENSES DO NOT HAVE CROP FACTORS! Imagers (sensors / film sizes) have crop factors, not your lenses. A focal length is a focal length. 50mm is ALWAYS 50mm, etc.. The only thing that differs from one lens system to another is the area it's designed to cover and the detail level at which it can resolve. Lenses designed to cover larger imagers will often have larger elements and larger physical construction. Likewise, lenses that are designed to transmit more light (faster), often grow in size to increase their light-gathering abilities. Master Primes are quite a bit larger than Ultra Primes for a few reasons. The combination of light-gathering ability along with multiple fine-tuned elements to minimize breathing and distortion, have come at the expense of physically larger lenses.

...Of course, it gets difficult to convince people that their lenses in fact do not have a crop factor. Especially when manufacturers like to label lenses with such factors based on the formats the lenses are intended to cover. On a point and shoot camera, that's OK. But when companies like Tamron and Samyang like to stamp APS-C/DX lenses with FF35mm equivalent focal-lengths, that to me is a problem. Thankfully, they still do the primary markings as the actual focal lengths, but I don't understand why they post the FF35 equivalent of the intended imager size on the lens, as if it actually has any real basis.

 

[David Rasberry]

Absolutely agree Jeff. Actual focal length and f-stop are the only lens values of relevance for determining DOF regardless of image format or crop factor. To label a lens with FF35 equivalents is misleading and of no real value.

 

[Alexander Ibrahim]

Using FF35 as a reference doesn't make a lot of sense for me -- you're suggesting that the majority of people here primarily shoot FF35 and thus have that range of focal lengths in their head. I shoot 35mm cine / Super-35 / APS-C / digital 35mm (Genesis, Alexa, F35, Red One, Epic, etc.) and have those focal lengths in my head... it takes some work to mentally convert them to FF35 equivalents. Very little filmmaking is done with FF35 formats (Canon 5D and VistaVision mainly) compared to 35mm cine, so why should FF35 be the basis for discussion on typical focal lengths used for filmmaking? FF35 is primarily a still photographer reference.

The main problem is that people in their posts don't label the format they are referring to, that's all, when they say that "this is equal to that..." in terms of equivalent focal lengths, hence the confusion. That and some people don't know that FF35 refers to 36mm x 24mm, and all of this is further confused by the fact that the M-X sensor is larger than Super-35 (30mm wide, not 24mm wide) and yet Red calls it a S35 sensor.

I agree with David 100%

Whenever I speak about motion imaging I am talking about S35 as my reference point.