Camera crop factor (1 Viewer)

tonky · Nov 8, 2007

Photovisions said:
Tonky

Your living proof that small pixels do help!
The Canon camera's with the smallest pixels are the 400D and 40D (see my table earlier in the thread), even smaller than the 20D

See, there you go, I hadn't even considered the 400D! Interesting! :t:

and I reckon the 40D is nearly the perfect camera for bird photography and fairly priced.
Go get it

Adrian

LOL. That's already looking like a racing certainty now in The New year probably. Don't get me wrong I could happily 'make do' with a 1DS MK3, but it's a sobering thought that for that sort of dosh you could buy a 40D body, a 600mm f4L, put change in your pocket and still put the larger 1:1 image on the sensor. |8.|

GYRob · Nov 11, 2007

tonky said:
See, there you go, I hadn't even considered the 400D! Interesting|

the 40d has better pixsel lenses so give better noise even though there the same MP's .
i dont have a 40d but found my 400d a bit lacking in the IQ when pushing it.
Rob.

Auntystatic · Nov 15, 2007

take a 6x4 picture and cut the middle out to give a 5x3 image, that will explain the 1.6 crop factor, and here is a picture and the canon link that explains it......

http://cpn.canon-europe.com/content/infobank/lenses/ef-s_and_field_of_view.do

Hope this clears it up for some of you, and which ever moron came up with the idea of magnification factor needs shot for causing so much confusion.

Canon has also said on their professional site, that film is still better than digital, as digital with 14bit processing gives 24bit colour, where as film has unlimited shades and colours, the limiting factor for film is in the digitising equipment used for use in printing.

kevindurose · Nov 15, 2007

I was looking the other night and I'm pretty certain that in the instruction book for my canon 20d it states when compared to film the sensor gives 'effective magnification' I guess the moron works at canon.

Keith Reeder · Nov 15, 2007

Not really, Kevin - Nikon cameras output the "35mm Equivalent Focal Length" to the Exif!

RAH · Nov 16, 2007

Auntystatic said:
take a 6x4 picture and cut the middle out to give a 5x3 image, that will explain the 1.6 crop factor, and here is a picture and the canon link that explains it......

Well no, it doesn't explain it. You are ignoring the idea that the smaller sensor may have as many pixels as the large sensor camera - i.e. the smaller area of your image is NOT smaller when taken by the small-sensor camera, it is the same size (width x height in pixels) as the full area taken by the large sensor camera. For example, comparing a 10MP large-sensor camera versus a 10MP small-sensor camera. Both produce the same size images, which is not what your internal crop picture shows.

We have fully explained this concept repeatedly in this thread, and everyone seems to be on the same page with it (but disagreeing on the MEANING of it), so I see no reason for you to try to reduce the issue to a misleading simplification. And calling people morons is what we like to avoid on this forum, IMHO.

graham catley · Nov 17, 2007

test

I have been intrigued by this thread and so did some test shots; photographed a lock on the garden shed from 8m with tripod mounted 3002.8 and 1.4 converter on my 1DIIN and 40D--within seconds; JPeg highest quality on both cameras; 400ISO f5, 200th sec
The out of camera images came out at
IDIIN 3504 x 2336 5.43MB
40D 3888 x 2592 3.25MB

To try and get things compatible with the forum I then had to reduce both originals to 800pix wide --posted as such here

I then cropped to the edges of the bracket round the lock (actually 12cm wide on the door) which made the 1DII image 823 x632 pix and the 40D 1168 x 912 pix; to see if there was a quality difference by enlarging the 1DII size tot eh equivalent of the 40D I used CS2 to resize the 1DII to 1168 wide; I have then sized both images down to 800 pix for the forum --I think this means I have done the alterations in tandem and I used the same setting in CS2 for altering each image; these 4 area attached here---see next post for next stage

graham catley · Nov 17, 2007

test 2

to continue the test I cropped further in on the lock (actually 8cm wide so small bird sized) and then increased the print size to 20cm at 300 dpi as per general magazine printing requirements of a small bird these were then scaled down to 800 pix
I then cropped down to the badge alone and resized it down to 800 pixels---

now which looks best? and is there a huge difference between the two methods ie bigger initial image in 40D or resized image in 1DII---

stevo · Nov 17, 2007

To my eyes at least there seems to be a shift in tonal range between the 2 cameras thus on my monitor the 1dmk11 looks to have better colour if this makes sense.

Steve.

AMM · Nov 17, 2007

RAH said:
Well no, it doesn't explain it. You are ignoring the idea that the smaller sensor may have as many pixels as the large sensor camera - i.e. the smaller area of your image is NOT smaller when taken by the small-sensor camera, it is the same size (width x height in pixels) as the full area taken by the large sensor camera. For example, comparing a 10MP large-sensor camera versus a 10MP small-sensor camera. Both produce the same size images, which is not what your internal crop picture shows.

It does explain one aspect of this discussion. Any camera with a sensor the same size as that of the 40D will capture on the sensor 1.6 times less of the image than a camera with a full frame sensor (assuming distance to subject and lens focal length are the same). That is physics!

The remainder of discussion about the relative quality of the captured image between different sized sensors is dependent on attributes of the sensor (e.g. pixel numbers and size) as has been well illustrated by several of the contributors to this thread..

IMHO it doesn't help when magazines like Amateur Photographer refer to a 'Focal length mag' of 1.6 when reviewing the 40D. Why don't they refer to it as a 'crop factor'?

Thats my little contribution to this thread!!!

Tony

Roy C · Nov 17, 2007

graham catley said:
to continue the test I cropped further in on the lock (actually 8cm wide so small bird sized) and then increased the print size to 20cm at 300 dpi as per general magazine printing requirements of a small bird these were then scaled down to 800 pix
I then cropped down to the badge alone and resized it down to 800 pixels---

now which looks best? and is there a huge difference between the two methods ie bigger initial image in 40D or resized image in 1DII---

Not a lot in it to my eyes but I think the 40D image of badge is a tad more detailed (sharper !). Of the whole Bracket images I think the 1D shades it.

CCRII · Nov 17, 2007

Keith Reeder said:
Actually,

I think that many folk really do believe that they're getting a real optical increase in focal length from the crop factor - you only have to see how people refer to it to get that impression.

Pretty much on a daily basis you see posts which clearly indicate that the user is of the belief that by using a 300mm lens (say) on a 1.6 crop camera they've got a 480mm lens.

The funny thing is that experts think this to. I wont name names, but there is at least one authority here in the US that is probably the top bird photographer that refers to the crop factor as adding focal length and has made reference to certain lenses for instance 500mm with a TC and then points out that with the cameras crop factor gets 1000+mm focal length. Kind of misleading.

Keith Reeder · Nov 17, 2007

That'll be Art Morris, I guess...

It's "experts" promulgating the "increased focal length" idea that has really caused the confusion in the first place, I reckon.

Photovisions · Nov 18, 2007

Its interesting that "crop factor" is not a misleading term, after all, that is exactly what the smaller chip camera's are, cropped, smaller chip.

I just can't understand how this can be misinterpreted, but it has?! Its unfortunate that people like Art Morris (if he did say this), who is hugely respected, gives misleading advice.
Adrian

GYRob · Nov 18, 2007

nice test Graham
the final shot shows the 40d to be better with more detail and that is very important with the smaller bird's that need a frame crop .
I might even buy a 40d now

Rob.

kevindurose · Nov 19, 2007

Excellent test, the 40d clearly wins. I dont think anyone would argue that the 40d provides actual increased magnification due to its crop factor. But having said this, it does have this effect, because it produces more fine detail when picture cropping is needed. It might not be magnification (increased focal length) but its not a simple crop either as suggested above by Auntystatic above.

Why do people have dismissive of the cheaper non-professional cameras?

gordon g · Nov 19, 2007

kevindurose said:
Excellent test, the 40d clearly wins. I dont think anyone would argue that the 40d provides actual increased magnification due to its crop factor. But having said this, it does have this effect, because it produces more fine detail when picture cropping is needed. It might not be magnification (increased focal length) but its not a simple crop either as suggested above by Auntystatic above.

Why do people have dismissive of the cheaper non-professional cameras?

I dont think that many people do, or at least not in terms of image quality. The test shots from Graham, show, if anything, that the 'non-pro' body actually has slightly better detail resolution when cropped (But just to stir a little, it was up against a 'pro' body from the previous generation - how would a 1DsIII do?

).
However, that's not the only point of a 'pro' body - there are also factors such as metering and focus systems (although the X0D series canons are probably nearly up there now judging from some of the 40D threads), armour and weather seals. My 1 series bodies (1V and now 1DsII) have coped with dust, water emersion, sand, snow, being dropped and tripods blowing over (and even being used by my children on occasion :eek!

and continued to function as they were meant to. I dont think some of the non-pro bodies would have made it - when my set-up was a EOS300 and a 1V, the 300 stayed at indoors!

kevindurose · Nov 19, 2007

Gordon, points taken, although one thing is for sure I aint gonna buy one to find out! I'm going for a 40d, if I drop it and it breaks I can get a new one. If I drop that one, I will probably go for the 40ds replacement version 2. And after this I will still have change to buy a big back-breaking canon lens. Seriously a pro camera means for professionals. A pro might go all the way to Antartica to hit point blank penguins and stuff, a camera failure here could be a bit of a problem. There is no need for cropping so why not use the bigger better quality sensor.

As you said it would be interesting to see a direct comparison between the 40d and the mark 3

CCRII · Nov 19, 2007

Photovisions said:
Its interesting that "crop factor" is not a misleading term, after all, that is exactly what the smaller chip camera's are, cropped, smaller chip.

I just can't understand how this can be misinterpreted, but it has?! Its unfortunate that people like Art Morris (if he did say this), who is hugely respected, gives misleading advice.
Adrian

I will not say who for legal concerns.

StrikingSlug · Apr 10, 2008

Apologies for resurrecting this thread, but my queries are probably relevant to its general gist.

Firstly, all the comments above relate to the extreme telephoto end of a lens. While of course that is important when it comes to birding photography, it doesn't tell the whole story. Standard kit lenses tend to be around the 18-55mm range. On an old SLR an 18mm lens would have been pretty much a fisheye, but on a DSLR that does not seem to be the case. To a non-expert that would seem to imply that the idea of magnification factor or crop factor does seem to have a degree of realism to it.

Secondly, and really where I am looking for advice, I currently only have a Canon 710IS compact with a 6x zoom. The instructions say this is equivalent to a 35-210mm lens, but is this really true? If I were to buy a DSLR and a lens close to 210mm (something like the Sigma 18-250mm for example) would I see the same magnification / field of view or would the performance be better?

Thanks,

Richard

Camera crop factor (1 Viewer)

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