Canon XF200/205

[Bruce Watson]

Originally Posted by David Heath

Not necessarily. Large sensor cameras only have shallower depth of field than smaller sensors ones if you compare at the same f stop.

So take a 2/3" sensor and s35 as an example, and if the 2/3" is at f2, you'll get identical depth of field on s35 at somewhere around f5.6.

This is true only if we're talking about the same focal length. For DOF, you have to compare at the same aperture, but also at the same focal length. Which is problematic when the sensor size is different, because a given focal length gives you different angles-of-view with different sensor sizes.

So if you use the same prime lens on the 2/3" camera as you do on the s35, then move the cameras relative to one another until the framing of the image is the same with both cameras, then you get the same DOF if you stop the s35 camera down an additional 3 stops from the 2/3" camera.

This is why people think, in practice, that a large sensor camera gives shallower depth of field than a smaller sensor camera. Because in practice light levels tend to dictate aperture, and distance to the subject tends to dictate focal length.

That's not to say that you can't get a reasonably shallow DOF from a 1/3" camera. I've seen interviews shot on 1/3" camera where the camera was shot through a door way and was in the middle of an adjoining room, just to get the distance from the subject needed so that the camera could use a long focal length (shooting nearly wide open), and the subject could be pulled far enough away from the background. Between the three (focal length, aperture, and subject's distance to the background), they got sufficient blurring of the background to make it work.

But it would have been a whole lot easier with a larger sensor. Which is what people mean when they say they can get shallower DOF with a larger sensor camera.

[David Heath]

Originally Posted by Bruce Watson

This is true only if we're talking about the same focal length. For DOF, you have to compare at the same aperture, but also at the same focal length.

Not so. My comment does deserve a caveat, but it's the same *angle of view* - not focal length.

(The other caveat I'm taking as read is same system resolution.)

If you keep the same focal length and aperture - but vary sensor size - the depth of field will stay the same, let's say between 5 and 7 feet. What will change will be angle of view - and hence that's why a large sensor can give shallow depth of field with a relatively wide angle lens.

If you change focal length with sensor size (to keep angle of view constant), then with the same f stop it's true the depth of field will change - it will be shallower with the large sensor/longer focal length lens. But stop down the appropriate amount (2 stops if you're quadrupling the sensor area and doubling focal length to compensate) and it's back to square one.

[David Heath]

Originally Posted by Emmanuel Plakiotis

David, since you are far more knowledgeable than I am, correct me if I am wrong.

Well, I'm not sure about the first bit of that....... :-)

No, your calculations are correct, but I may have been clumsy with my original statement and misled you.

Originally Posted by Emmanuel Plakiotis

with my calculations...Knowing that total pixel count is 2910000, the difference between the actual and effective image area is 5.34% which translates into 155394 pixels.
If we subtract them from the total, that leave us with 2754606 pixels which are 681006 more than the nominal HD resolution of 2073600 pixels (1920X1080) or 32,84%.
In theory and according to your 25% rule is adequate for a true 1080 debayered image.

The "25% rule" is normally taken on a linear photosite count and my apologies for not making that clear. Same with "preferably 50%", which is what the Alexa does - it's 2880 horizontally, or 1.5x1920. (Likewise 1.5x vertically.)

So talk of total numbers and you'd really expect (at least) 1.25x1.25 as many (56% extra), preferably more - in the case of the Alexa it's 125% extra!

If you go down the oversample, deBayer, downscale route it's a lot of extra processing and I'd only expect it to be used when well worthwhile. And doing all that work for only 32% extra photosites somehow seems a lot of work for not that much potential gain........ But this is all theorising.

[Les Wilson]

Originally Posted by Ed Arszyla

The shallow DOF in large sensor cameras would be a problem for run & gun ENG work. Likewise would the lack of a long servo zoom for most cinema cameras.

Yes. I think everyone understands that. My quoted post intentionally uses the phrase "some of the same things" referring to the reality of the middle area between the extremes where either can be used for the same thing.

I think good examples are documentary and wedding work. You can shoot an interview with either a Cinema and an ENG camera but you use both in the production... some at the extremes and some for the same thing. Sometimes you use the one you have with you, or both as interview A and B cameras. Then pack up and shoot some b-roll with an ENG and some with SDOF with Cinema ... some other b-roll or stand up with large DOF using a Cinema ... some SDOF with either, depending. There's plenty of stuff that either can be used for with certain conditions and tradeoffs.

To the point of this sub-discussion, a single chip small sensor has resolution and light sensitivity differences (usually inferior) vs a 3 chip small sensor. And Philip's point was moving from the small single sensor XF100 to a C100 with a single large sensor gave a noticable improvement in resolution. Presumably shooting the same stuff he was shooting with the XF100... aka the middle.

[Bruce Watson]

Originally Posted by David Heath

Not so. My comment does deserve a caveat, but it's the same *angle of view* - not focal length.

If you read the rest of my opening paragraph, I think you'll find that we are in agreement even if we say it differently. What I said was:

This is true only if we're talking about the same focal length. For DOF, you have to compare at the same aperture, but also at the same focal length. Which is problematic when the sensor size is different, because a given focal length gives you different angles-of-view with different sensor sizes.

[Mark Fry]

I've seen quite a lot of output from the XF100, and it's very impressive. It gives a significantly better image on Blu-ray and down-scaled to DVD than my XH-A1 (same edit/production chain), and is usefully smaller and lighter. The 2 things that kept me from blowing £££s on an XF100 were the relatively short reach zoom and the lack of the zoom-speed thumb-wheel, that most handy gadget on the XH-A1 and XF300.

Looks like the XF200 answers the first lack, but what about the second? Looking closely at the images posted at the top of this thread, I don't anything that looks like a zoom-speed wheel behind the rocker, just a still shutter. Have I missed it?

[David Dixon]

I don't know what a zoom speed thumb wheel is, but if it refers to controlling the maximum zoom speed, on the XF100 there is a menu to choose the maximum speed of the zoom - I think there are 3 speed options. And, independent of each speed, you have the option to turn on or off the zoom rocker speed sensitivity - barely press for a slow creep, press further at any time to speed it up. And you have the option to turn on or off a soft landing that slows down slightly when you near the widest or longest extremes of the zoom.

Is that what's meant? And I don't know if the XF200 series retains all these options, but I can't believe it doesn't. In fact, has anyone discovered anything at all yet that the 200s drop that are found on the 100s?

[Les Wilson]

@David, The A1 zoom speed wheel gave you more speeds than H, M and L. It was also faster than drilling into the menu... easily adjusted while shooting or while running to the next gunning. Better ergonomics.

I'm expect that kind of thing is gone for good.

[Mark Fry]

Originally Posted by David Dixon

I don't know what a zoom speed thumb wheel is, but if it refers to controlling the maximum zoom speed, on the XF100 there is a menu to choose the maximum speed of the zoom - I think there are 3 speed options. And, independent of each speed, you have the option to turn on or off the zoom rocker speed sensitivity - barely press for a slow creep, press further at any time to speed it up. And you have the option to turn on or off a soft landing that slows down slightly when you near the widest or longest extremes of the zoom.

Is that what's meant? And I don't know if the XF200 series retains all these options, but I can't believe it doesn't. In fact, has anyone discovered anything at all yet that the 200s drop that are found on the 100s?

Both the XF300 and the older XH-A1 have a constant/variable selector switch and a little wheel beside the zoom rocker. When constant is selected, the wheel allows you to dial in the exact zoom speed you want, and to change it during a shot very precisely. There are 16 steps and transition between speeds is pretty smooth. Within the menu, there are three speed ranges to choose from: slow, medium and fast. On the slow range, click 1 takes over 5 minutes to get from one end to the other; on the fast range, click 16 is a real "crash zoom". I struggle to keep an even speed on rocker switches (I've used several different Canon, Sony and Panasonic cameras over the years) so the thumb-wheel on the XH-A1 has given me the level of control I've always wanted.

Les - why do you say "I'm expect that kind of thing is gone for good"? It proved very popular on the XH-A1 and they put it on the XF300 too. Maybe they can't (or don't want to) put it on the smaller cam, but what makes you think they'd drop it completely?

[Scott Hiddelston]

Originally Posted by David Dixon

I don't know what a zoom speed thumb wheel is, but if it refers to controlling the maximum zoom speed, on the XF100 there is a menu to choose the maximum speed of the zoom - I think there are 3 speed options. And, independent of each speed, you have the option to turn on or off the zoom rocker speed sensitivity - barely press for a slow creep, press further at any time to speed it up. And you have the option to turn on or off a soft landing that slows down slightly when you near the widest or longest extremes of the zoom.

Is that what's meant? And I don't know if the XF200 series retains all these options, but I can't believe it doesn't. In fact, has anyone discovered anything at all yet that the 200s drop that are found on the 100s?

David, I could be all wrong here but I can't find any article that says the 200 series records 720p, something the 100 series does. so no 60p in MPEG2 at all?

[Les Wilson]

Originally Posted by Mark Fry

...Les - why do you say "I'm expect that kind of thing is gone for good"? It proved very popular on the XH-A1 and they put it on the XF300 too. Maybe they can't (or don't want to) put it on the smaller cam, but what makes you think they'd drop it completely?

I thought it was a great feature. I didn't know it made it to the XF300. Awesome.

All I meant by my comment was sometimes good features, once they disappear, don't seem to come back. In this case, I was wrong, it hasn't disappeared. Yet. :-)