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In the Pro and Apprentice section Lee ( the apprentice ) states that he didnt know his 400d had a crop factor 1.6x which made his lenses longer :shrug:

What is the crop factor ? is it some thing that can be done on the camera itself or through photoshop etc.... also what would a 55-250mm be with this in affect.

Cheers
 
Crop Factor means that the sensor size is smaller than full frame 35mm by a factor of 1.6 which means that the image gets cropped, giving the effect of a longer lens, i.e. a 100mm lens on your 400D will produce the same image as a 160mm on a 35mm camera.

Note that it doesn't actually increase the focal length of the lens.

BTW, I've just subscribed to PhotoPlus - the LowePro bag free gift looks good :thumbs:
 
Thanks for that Parish, i been thinking of subscribing myself, very helpfull magazine.

Cheers
 
Shooting with both D2X and now the D3 upgrade, it isn't just a straight crop effect that happens, you also get a loss of light to the same degree.

Taking the same subject on both bodies with the same lens you get a faster shutter speed for the same aperture on the full frame - exactly like you get a telephoto addition by using a multiplication conveerter (teleconverter) at the expense of light loss
The D2x has a multiplication factor of 1.5 - which means a standard 50mm lens has the same image circle coverage on the D2X sensor of a 75mm lens circle on 35mm film. A 1.5x magnification. At the same time, you get a decrease of light transmittance - so even with f2.8 set, you are in effect using f4.5 from a light transmittance point of view. Depth of field is also slightly deeper with the cropped sensor over the full frame one.

That said, I am still keeping one of my D2x bodies to use when I don't want to lug a load of heavy lenses around with me - its great having the reach of a 300 with the 70-200! The only drawback with cripped sensors is the wide angle end - but I only had ot buy a 12-24 and I was fully covered again, except for the fisheye (and I lost that one overboard on a boat shoot a couple of months ago!)

I digress. Sensor crop has the same effect as a teleconverter. You get a longer reach and a corresponding loss of light.
 
Lensflare said:
Sensor crop has the same effect as a teleconverter. You get a longer reach and a corresponding loss of light.
Click to expand...
Sorry, but that's just rubbish.
 
StewartR said:
If you mean, does your 450D have the same size sensor as a 400D, then the answer is yes.
Click to expand...

Sorry didn't ask the right question!!

Does my 450d have the sensor crop feature, like the one talked about in the magazine? I have to say, I read that and was a little confused.
 
swag72 said:
Does my 450d have the sensor crop feature, like the one talked about in the magazine? I have to say, I read that and was a little confused.
Click to expand...
I think you were confused.

It's not a "feature". It's just the size of the sensor. The sensor in the 400D and the 450D is smaller than a frame of 35mm film. That's all it means.
 
parish said:
Crop Factor means that the sensor size is smaller than full frame 35mm by a factor of 1.6 which means that the image gets cropped, giving the effect of a longer lens, i.e. a 100mm lens on your 400D will produce the same image as a 160mm on a 35mm camera.

Note that it doesn't actually increase the focal length of the lens.

BTW, I've just subscribed to PhotoPlus - the LowePro bag free gift looks good :thumbs:
Click to expand...

Do you happen tp have a link to the offer by any chance.......

Sorry Being lazy and not walking to the new agents
 
Lensflare said:
I digress. Sensor crop has the same effect as a teleconverter. You get a longer reach and a corresponding loss of light.
Click to expand...

:thinking: :nono:

StewartR said:
Sorry, but that's just rubbish.
Click to expand...

I agree! That statement is completely wrong.

There is no loss of light when using a crop sensor. A lens with an aperture of f2.8 will let the same amount of light through whether you have a full frame body or a crop body.
 
All the lower end Canon models have smaller sensers, 300D, 350D, 400D, 450D, 20D, 30D, 40D. If i'm right in saying that.
 
parish said:
Crop Factor means that the sensor size is smaller than full frame 35mm by a factor of 1.6 which means that the image gets cropped, giving the effect of a longer lens, i.e. a 100mm lens on your 400D will produce the same image as a 160mm on a 35mm camera.
Click to expand...

I've been thinking about the effects of the crop factor after reading lots of different interpretations on it and I think I've got it straight...

Since the characteristics of a lens aren't changed (it's the sensor in the body that changes), the image from a 100mm lens on a (1.6X) cropped body isn't going to be the same as that from a 160mm lens on a full frame body.

By that logic, that 60mm difference in focal length is going to result in a different amount of telephoto compression effect so you get the same angle of view of a 160mm lens, but the telephoto compression effect of a 100mm lens.
 
DigitalRelish said:
I've been thinking about the effects of the crop factor after reading lots of different interpretations on it and I think I've got it straight...

Since the characteristics of a lens aren't changed (it's the sensor in the body that changes), the image from a 100mm lens on a (1.6X) cropped body isn't going to be the same as that from a 160mm lens on a full frame body.

By that logic, that 60mm difference in focal length is going to result in a different amount of telephoto compression effect so you get the same angle of view of a 160mm lens, but the telephoto compression effect of a 100mm lens.
Click to expand...

Here's a graphical explanation.

The first pic is what you would get with a 35mm full-frame camera.

The second is what you would get with a 400D - or other APS-C sized sensor - if taken with the same lens from the same position:

italian_day_08_0028-800.jpg



italian_day_08_0028-500.jpg


To get the same composition with a 35mm full-frame (taken from the same distance) you'd need to use a lens with a focal length 1.6 times greater.

Edit: Perhaps this illustrates 'crop' better - the coloured area represents the 400D sensor, the whole pic represents the 35mm full-frame. So, part of what the lens 'sees' falls outside the sensor area giving the effect of a longer focal length.


italian_day_08_0028-800x.jpg
 
Thanks for making the effort to add graphics, but I'm happy with the concept of a cropped sensor only providing a proportion of the image a lens projects.

The bit I was questioning, and I might be reading you too literally, is

parish said:
a 100mm lens on your 400D will produce the same image as a 160mm on a 35mm camera.
Click to expand...

What I'm saying is that a 100mm lens on a 400D will not produce the same image as a 160mm on a full frame camera because a true 160mm lens will provide a different perspective on objects in the field of view than a 100mm lens.

The group of four photos of the yellow structure half-way down this page demonstrate what I mean.
 
DigitalRelish said:
Thanks for making the effort to add graphics, but I'm happy with the concept of a cropped sensor only providing a proportion of the image a lens projects.
Click to expand...

Ah, sorry, misunderstood your post :bonk:

DigitalRelish said:
What I'm saying is that a 100mm lens on a 400D will not produce the same image as a 160mm on a full frame camera because a true 160mm lens will provide a different perspective on objects in the field of view than a 100mm lens.
Click to expand...

Indeed, the perspective will be different, I was meaning the reduced field of view - but then I'd misunderstood your post so.... :bonk:
 
No worries. Like I said, I was probably reading it too literally or just not explaining myself clearly enough. :)
 
parish said:
Crop Factor means that the sensor size is smaller than full frame 35mm by a factor of 1.6 which means that the image gets cropped, giving the effect of a longer lens, i.e. a 100mm lens on your 400D will produce the same image as a 160mm on a 35mm camera.

Note that it doesn't actually increase the focal length of the lens.

BTW, I've just subscribed to PhotoPlus - the LowePro bag free gift looks good :thumbs:
Click to expand...


That was to good to miss sent off my D/D today :).

Regards Mark
 
Hi is this right, If you use a cropped camera IE 400D and so on, then upgrade to full frame camara , can the Len's you used on the cropped one be used on the full frame,

Regards Mark.
 
Yes mercman, unless the lens was made specifically for cropped sensors, like the Canon EF-S range or the Sigma DC range, if you try to use one of them you risk damaging the camera as it can trap the mirror.
 
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