Canon Crop factor: Have I got this correct?

EdBray

EdBray

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Edward Bray
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I have a Canon 1DsMk3 and a Canon 1DMk3.

The 1DsMk3 has a maximum resolution of 5616 x 3744 pixels on a sensor with a size of 24mm x 36mm which gives 21MP divided by 864 mm2 equals 24.336 pixels per mm2 density.

The 1DMk3 has a sensor size of 28.7 x 18.7mm (537mm2) with a maximum resolution of 3888 x 2592 pixels (10MP) which gives 18.766 pixels per mm2 density.

If I crop the 1DsMk3 image to the same size as the 1DMk3 sensor I would have a 537(mm2) x 24.366 (1DsMk3 pixel density) = 13.1MP

So aside from the extra stop of high ISO and 10fps, by using the 1DMk3 over the 1DsMk3 and cropping I lose 3MP of resolution?
 
:thinking:

wish life was so simple
 
Ed, I haven't checked your maths but I am sure you are right. Certainly the 5D2 (equal to the 1Ds3 in pixel count and sensor size) has more reach (higher pixel density) than the 1D3. I've just never done the maths to work out the exact figures.

FWIW the pixel density of the 1Ds3/5D2 is equivalent to a 30D, and thus offers as much reach as the little cropper.
 
EdBray said:
So aside from the extra stop of high ISO and 10fps, by using the 1DMk3 over the 1DsMk3 and cropping I lose 3MP of resolution?
Click to expand...

Perhaps an alternative way of looking at things would be clearer Eddie.....

Your 1Ds3 has 156 pixels/mm whilst the 1D3 has only 135 ppm.....a 15% reduction in "capturing power" or "cropability"
Bear in mind that you need two pixel rows/columns to resolve a line pattern and you're looking at 78 line pairs/mm as opposed to 68 lpm.

Stick a decent lens on the front, we'll say a 135/2 L at f/4, and it can provide 145 lpm to the sensor from its centre portion....nothing to concern us there. However, opt for a shoddy consumer zoom that'll only give you 65 lpm around the edges and things have been levelled out a tad. So, not an issue with the lenses likely to be paired up with 1 srs bodies but an 18Mp 550D isn't going to cut it with a cheapo zoom.

Bob
 
Hi Bob,

I am looking at the best option for general photography with only one body.

It would seem to me that provided I did not need an extra stop of high ISO and greater than 5fps then the 1DsMk3 will do everything and more than the 1DMk3 will.

If I can crop an image from the 1DsMk3 to a similar size or greater than that produced by the 1DMk3 but keep the quality then other than for backup I can see little reason to have the 1DMk3.

Shoddy consumer zoom? What's one of them?

Current lens line-up (may change as you know it's quite fluid):

Canon EF16-35L MkII, Canon EF17-40L, Canon EF24L TS-E MkII, Canon EF50 f1.8 Mk1, Canon EF65 MP-e, Canon EF85L MkII, Canon EF100L IS Macro, Canon EF135L, Canon EF200L f2.8 MkII, Canon 300L f4 IS, Canon EF 1.4x Extender MkII
 
EdBray said:
Hi Bob,

I am looking at the best option for general photography with only one body.

It would seem to me that provided I did not need an extra stop of high ISO and greater than 5fps then the 1DsMk3 will do everything and more than the 1DMk3 will.

If I can crop an image from the 1DsMk3 to a similar size or greater than that produced by the 1DMk3 but keep the quality then other than for backup I can see little reason to have the 1DMk3.

Shoddy consumer zoom? What's one of them?

Current lens line-up (may change as you know it's quite fluid):

Canon EF16-35L MkII, Canon EF17-40L, Canon EF24L TS-E MkII, Canon EF50 f1.8 Mk1, Canon EF65 MP-e, Canon EF85L MkII, Canon EF100L IS Macro, Canon EF135L, Canon EF200L f2.8 MkII, Canon 300L f4 IS, Canon EF 1.4x Extender MkII
Click to expand...

The 5Dmk2 crops very well, certainly a 1.3 crop wouldn't cause many problem unless you are printing at huge sizes.

As the 1Dsmk3 is arguably a slight more capable performer in imaging terms than the 5Dmk2 then you shouldn't have any problems.

It sounds like you don't need the frame rate of the 1Dmk3 and you are packing some top quality glass. Hence the 1Dsmk3 may be the best compromise. If you could ever call a 1Dsmk3 a compromise....
 
Eddie

I went through a similar thought process, which is what lead me to use a 1DsII for a few years for wildlife. Now the 1DIV has come along, I've moved onto that as it offers further pixel density if useful. I went through the same decision with the 1DII and 1DsII and picked the Ds.

Paul
 
A 1Ds3 is a very expensive solution to the "problem". As a "do it all" camera it is an OK, if rather archaic choice, but for less money you could have a 1D3 and a 5D2, or a 1D3 and a 7D, or a 5D2 and a 7D. That way you have cameras better suited to specific disciplines rather than one body that is not very fast, not great at high ISO and not exactly pushing the boat out on pixel density.

I know it's not apples to apples, but two capable bodies for the price of one is an attractive proposition, meaning you have a backup body in the event of tragedy and can travel with a two body setup to speed up shooting and avoid lens changes. Also, if the fancy takes you you can travel with a lighter and more compact solution rather than permanently dragging a 1 series around all the time.

Personally I prefer to run with a 7D, 1D3 and 5D2 as it provides greater flexibility and redundancy. I also get a decent LCD screen and decent Live View, with Live AF on two of the three. Horses for courses, of course. :)
 
tdodd said:
A 1Ds3 is a very expensive solution to the "problem". As a "do it all" camera it is an OK, if rather archaic choice, but for less money you could have a 1D3 and a 5D2, or a 1D3 and a 7D, or a 5D2 and a 7D. That way you have cameras better suited to specific disciplines rather than one body that is not very fast, not great at high ISO and not exactly pushing the boat out on pixel density.
Click to expand...

I have to disagree here Tim. OK, my experience was with a 1Ds2 but it is a great solution to the problem. Seems strange to call it archaic - it's amazing how the world's expectations around camera bodies are so short term these days!

You get superb AF, excellent image quality, excellent build quality, etc.

I have to say that I really don't think the IQ on my 1D4 is that much better than it was on my 1Ds2. There are other improvements but it is probably the worst value for money investment I've made in recent years. Not that I dislike the camera, just the improvement wasn't that great as the 1Ds2 is that good. What I really liked was the ability to go a bit wider if necessary but have enough pixels to crop and still get a decent print if required.

The 1Ds2 gave me a cropped image, taken at ISO1600, printed at A3 that is now in a national exhibition - doesn't sound like dreadful high ISO at that point.

Sometimes a single, flexible body makes sense, especially in hostile environments where you don't want to be changing lenses.
 
After reading Tim's 'archaic' comment, my 1Ds "older than the sun" classic is now sat in the corner crying its eyes out :suspect: :lol:
 
Actually I saw nothing in Ed's post to suggest consolidation was required, merely a query regarding the reach advantage of the full frame 1Ds3 over the crop body 1D3. Anyway, I played the "horses for courses" card. :)

As for changing lenses in the field, or not, surely the whole point of two bodies is that you can shoot wide and long without changing lenses. With one body only you're a bit limited. By today's standard I also don't consider 1600 ISO to be "high". Four years ago that might have been true. Today, really not. I've had to shoot at 3200 ISO at weddings and I've had to shoot indoor sports at 6400 ISO. I'd say that 1600 ISO, along with 800, is no more than mid level these days.

If you don't push the envelope particularly in any direction then I'm sure a general purpose camera like the 1Ds3 will suit you a treat, but if you have more specialised or more demanding needs then you need the right tool for the job. That often means having different tools at your disposal.
 
trencheel303 said:
After reading Tim's 'archaic' comment, my 1Ds "older than the sun" classic is now sat in the corner crying its eyes out :suspect: :lol:
Click to expand...

There's no need for it to do that. My old VHS recorder will still play back tapes as well as it did ten years ago, but it ain't no competition for Blue-Ray. Technology moves on and a lot has happened in the last three years. There's no harm in nostalgia, but don't let it get in the way of reality.
 
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