What kind of lenses are you planing to use

[Alister Chapman]

Focal length is focal length. It is a measure of how strongly the lens converges light or it's magnification power. It does not matter how big the sensor, mount, or anything else. Focal length is what it is. So I can take a 8mm C mount lens and stick it on a 75mm film camera and it will still be an 8mm lens. However on the 75mm camera only the tiniest circle in the centre of the frame would be illuminated by a lens designed for C mount applications (typically 2/3" or 16mm film maximum).

It is the size of the sensor that governs the field of view (FOV). A bigger sensor will have a wider field of view, assuming the lens can illuminate the entire sensor. So it's really important to think about the magnification or crop factor as applying to the camera, not the lens.

Talk to a film cameraman and to him (or her) a 50mm lens is a 50mm lens. The film guys know that they will have different FOV's depending on whether they are shooting S35, S16, 75mm etc, but they will still refer to the lens as 50mm. This prevents confusion. If you start talking about this lens being the equivalent to that lens it just adds to the confusion as it's dependant on the camera, not the lens. It would be better to say that "x" camera is the equivalent to "y" camera with a 30% increase in FOV.

Sorry, bit of a bee in my bonnet about this as I find it extremely confusing when people start asking me to shoot with a focal length the equivalent of....... Unless you know how big the sensor you have is compared to the sensor they are referring to it can be confusing. Really we should all be talking about FOV in degrees, then there would be no confusion, but that's not how us video guys have been brought up.

Super35 and the C300 are more or less the same size. So a lens on a S35 film camera will give the same FOV on the C300. However there are different sizes of 35mm movie frame, not just S35 and most good PL lenses can cover all of the different 35mm movie standards, but with slightly different FOV's.

Any lens manufacturer adding a multiplier to the true focal length of the lens should be shot for adding to the confusion.

[Alister Chapman]

Much to my surprise PIC on the C300 works with the rather horrid 18-55mm IS EF-S kit lens supplied in many of Canon's DSLR kits. Just as well as it's really dark in the corners!

[Robert Sanders]

I completely understand what you are saying. However, if you are used to an 18mm on a 35mm camera and you want an equivalent using an EF lens than you have to take that into consideration.

"What do you mean the lens isn't wide enough? It's an 18mm for crying out loud!" My response, "I understand, but a 18mm EF lens on a a C300 looks more like a 28mm."

So, if I were buying a PL C300 I would want in my kit a 24mm, a 35mm, a 50mm and an 85mm. However, if I were buying an EF C300 and plan on using EF lenses than my kit would have to change to a 18mm, 24mm, 35mm and a 50mm.

[Jon Fairhurst]

Originally Posted by Robert Sanders

So, if I were buying a PL C300 I would want in my kit a 24mm, a 35mm, a 50mm and an 85mm. However, if I were buying an EF C300 and plan on using EF lenses than my kit would have to change to a 18mm, 24mm, 35mm and a 50mm.

That's not quite right. For a 5D2 or other full frame camera, you might want 24, 35, 50, and 85, but for an APS-C or Super 35 camera you would want 18, 24, 35, and 50. The mount doesn't change things. The target market doesn't change things.

As an example, on a full frame still camera, a 50mm is a normal lens. On a medium format camera 50mm is wide. On a large format camera, it's ultrawide. On a crop or Super 35 camera 50mm is a moderate telephoto. On a 1/3" camera, it's a long telephoto. Whether the 50mm lens was made for a small spy cam or an observatory, a 50mm lens will always behave as I just stated on the various camera formats.

[Emmanuel Plakiotis]

Originally Posted by Mark Watson

A listing of Canon lenses compatible with the C300.

http://cweb.canon.jp/cinema-eos/spec.../structure.pdf

Mark

Although I don't understand Japanese, I think is a list of all Canon lenses that can be attached to the camera, not a list of lenses that fully cover the image area of the sensor.

[Alister Chapman]

Originally Posted by Robert Sanders

So, if I were buying a PL C300 I would want in my kit a 24mm, a 35mm, a 50mm and an 85mm. However, if I were buying an EF C300 and plan on using EF lenses than my kit would have to change to a 18mm, 24mm, 35mm and a 50mm.

But that's not right. A 24mm PL mount lens is the same as a 24mm EF-S lens. So if you want the same FoV on both the PL version or the EF mount version you would want lenses with the same focal length. As I said, a 24mm lens is a 24mm lens, no matter what the mount and as the sensor is the same on both versions of the camera, you want the same focal lengths. The conversion factor applies to the Field of View of the camera IF it is needed, the focal length of the lens does not change.


The confusion comes from the fact that when people talk about 35mm film based stills cameras and full frame sensor DSLR's (like the 5D), the film frame is larger than a 35mm movie camera (or APS-C camera). This is because in a stills camera the film runs east-west (horizontally), so the frame size is governed by the height of the film and the frame can be quite wide. In a 35mm movie camera the film runs north-south (vertically) so the frame size is restricted by the film width. As we shoot images that are wider than they are tall, this means that the movie frame, restricted by the width of the film, must be smaller than the stills frame.

So yes if you put a 24mm lens on a 35mm film stills camera or a 5D the field of view will be 30% wider than if you put that same 24mm lens on S35mm movie camera, C300, F3, FS100 etc. But it's still a 24mm lens whether Arri PL or Canon EF-s and a 24mm lens on a S35mm film camera will give approximately the same FoV as a 24mm EF-S lens on a C300.

A film trained DoP or Cinematographer won't think in terms of conversion factors as for him/her a 24mm lens is a 24mm lens and the FoV he is used to seeing on his 35mm movie cameras will be almost exactly the same as he will get on a S35 video camera.

[Charles Papert]

Alistair is correct.

It's been a confusing couple of years with the DSLR's and their different target sizes, but we are getting back to some semblance of order again with the new cameras conforming to the Super35 standard (give or take). Few things were more confusing than the gigs I did with combinations of the 5D, 7D and 1D (sometimes all three) where I had to constantly calculate which primes should go on which camera. I look forward to the end of all that...for the time being!

I have a feature coming up in April and I'm strongly considering the C300 for it. I'll be well covered with my Aluras (and will probably add a set of CP2s for handheld/Steadicam) assuming I can get the PL version of the camera, but it's risky considering it's only due to ship just a few weeks before our start date. I could still go EF with the CP2's, or even my ZE's (considering I'd make the rental, probably would go that route) but the dearth of cinestyle zooms with EF mount is a problem. Not sure when the Canons will emerge into the wild. Too many factors to make this easy. Sure wish the mounts were field-swappable.

[Mark Watson]

I'm working on getting a translation of that section.

From the Canon FAQ page....

What different EF lenses can I use with the EOS C300?
The EOS C300 is compatible with the following:
All Canon EF lenses (including Tilt-Shift, MP-E, etc.)
Canon EF-S lenses (there may be some visible vignetting with certain EF-S lenses)
Canon Cinema EF lenses – zoom and fixed focal length

Will all Canon EF lenses work with the C300?
Yes. Every Canon EF lens, including special-purpose lenses such as TS-E (tilt-shift), macro and MP-E lenses, fisheye lenses, and Canon super-telephotos will mount on the EOS C300 camera.

How does peripheral illumination correction work for EF lenses?
Peripheral Illumination Correction automatically corrects for any lens vignetting, accounting for specific lens characteristics such as focal length, working aperture, and distance setting. This produces even illumination across the frame, from center to corner. Canon engineers thoroughly test different Canon EF and EF-S lenses, map-out the specific vignetting characteristics of each lens, and this data is input into the camera. As images are taken, the camera records this information, and lens-specific correction is applied during in-camera processing to minimize the natural darkening that would otherwise occur toward the edges of video images.

Which EF lenses are compatible with the C300's peripheral illumination correction?
The EOS C300 stores Peripheral Illumination Correction Data for approximately 96 EF and EF-S lenses.

With reports that the ultra wide EF-S 10-22mm is okay on the C300 and the fact that over 90 lenses have PIC data in the camera already to address the issue of vignetting, it almost sounds like a non-issue. Probably why there's no list of unacceptable lenses is it's down to personal preference of how much vignetting is objectionable.

Around here we just use the term 'apparent focal length' when discussing a particular lens on a crop factor camera. Everybody wins.


Mark

[Emmanuel Plakiotis]

Since in the list there are only 71 lenses, there must be PIC's for defunct or non Canon lenses as well, to justify the 96 profiles.

[Robert Sanders]

So basically the same lens on a C300 has roughly the same FoV as the same lens on the C300-EF. Or roughly .90 of it.

[Alister Chapman]

The same lens on a C300 EF would have exactly the same FoV on a C300 PL.

Of note is that during my side by side tests with an F3, I discovered that the FoV with the same lens is wider by about 10% on the C300 than the F3. Given that the F3 sensor is already bigger than a Canon APS-C sensor, then the C300 must be quite a bit bigger than APS-C, so you will need to watch for vignetting with EF-S lenses.

[Emmanuel Plakiotis]

Alistair, if I remember correctly rougly corresponds to 1.3X as in 1D markIV.

In regard with the focal length:
The lens is essentially a light covergence device, that can project and magnify an image.
The magnification ability of the lens, is determined by:
the focal length (the distance from the lens, where the projected image is in focus), which is inherent in the lens design.
the size of the image sensor (the area of the projected image that is captured for processing).

Therefore the same lens can give different magnification, in accordance to the size of the sensor. Is easily deducted, that the smaller the sensor the bigger the magnification ability of the lens, because a smaller part of the projected image is used.

[Mark Watson]

Some translation.

[Alister Chapman]

Originally Posted by Emmanuel Plakiotis

Therefore the same lens can give different magnification, in accordance to the size of the sensor. Is easily deducted, that the smaller the sensor the bigger the magnification ability of the lens, because a smaller part of the projected image is used.

NO. The magnification of the lens is exactly the same. It is the Field of View that changes due to sensor size differences. The smaller the sensor, the narrower the FoV. The magnifying power of the lens does not change with sensor size. That's like saying, if I show my video on a bigger screen the magnifying power of the camera lens is increased because the image I see is bigger, but we all know that is not the case. Changing the sensor size only alters the FoV. FoV and magnification are two different things, the on screen results in changes of the two may appear similar, but they are still quite different things from an optics and lens point of view.

I might be being pedantic and perhaps I'm obsessing over this, but unless people start to learn and understand exactly what is going on with focal length and sensor size, the confusion will continue, which may end in people spending lots of money on the wrong lenses.

[Emmanuel Plakiotis]

Thanks for the correction Alister. You are absolutely right. By using a smaller area of the projected image, we change the perceived view, not the actual ability of the lens to converge light. I had it wrong straight from university. And is a long time ago...