could somone explain this to me or post a link that does

[boxer82003]

i read this somewhere a bit confused

Most DSLRs have a crop factor due to the image
sensor being smaller than 35mm film.

what does this mean ?

a simple answer to this if you can thank you

[scottbergerphoto]

i read this somewhere a bit confused

Most DSLRs have a crop factor due to the image
sensor being smaller than 35mm film.

what does this mean ?

a simple answer to this if you can thank you
It means that the physical size of the sensor is smaller then the size of a 35mm negative or slide. That means that there is a crop factor to reflect the change in apparant magnifcation by the lens. For the 10D and 300D, you multiply by 1.6 x the focal length of the lens to reflect that using a particular lens on a 10D/300D looks like the a picture taken on 35mm film with a lens 1.6X as long as the lens you are using.
Regards,
Scott

[vfilby]

I have wondered just what the difference is between crop and maginfication. I am assuming that of all the light normally let in by a lens the sensor is only using a small square in the middle. So it would be similar taking a 35mm negative and cutting out a small square in the center?

I think some digital companies are starting to advertise that the "magnification factor" is a feature. Where as I don't see it as a magnification factior at all.

Any comment on whether this assumption is correct?

Thanks,

[Jim_T]

I am assuming that of all the light normally let in by a lens the sensor is only using a small square in the middle. So it would be similar taking a 35mm negative and cutting out a small square in the center?


Exactly.. That's all there is to it.

35mm lenses are designed to focus to an area that covers a full 35mm frame. 10D/300D sensors are smaller than a 35mm frame. Because of that, all of the focused image created by the lens doesn't fall on the sensor. What falls outside the sensor is considered to be 'cropped'.

There is no magnification when you take the picture. Just an apparent reduction of the lenses field of veiw or, an apparent increase in the lens' focal length.

But if you print the smaller image at say 6 X 4, then you have to ENLARGE the image more to get it to that size, because the image captured by the sensor is smaller than the image caputred by a full 35mm frame sensor. You have to enlarge a 10D or 300D's image 1.6 times more. This is what causes the magnification.

.

[robertwgross]

So, there isn't any real 1.6x magnification in the lens. The only time there is any apparent 1.6x magnification is when you get a full print done from the captured image. However, if you study the sharpness of the print, you will discover that it is different from the sharpness of a full frame image of the same scene. If you shoot a full frame, and then crop the middle of it, and then print that to the same size, you will get the same result.

That is why some people like to refer to it as a 1.6 crop factor. Others like to refer to it as a 1.6 magnification factor. Others call it something else. We don't want to start another religious war over it.

---Bob Gross---

[vfilby]

Thanks gents, I appreciate your responses. I hope you didn't mind boxer, I hijacked your thread but I thought it was close enough to the original question not to be obtrusive.

[robekert]

Here is a link that illustrates the "crop factor" well.

http://www.luminous-landscape.com/tutorials/understanding-series/dslr-mag.shtml

Hope this helps,
Rob

[boxer82003]

no prob vfilby

im still learning the more info the better

[mdude85]

for all practical purposes, the magnification factor means the same thing as the crop factor. some companies may advertise it as a perk when dealing with telephoto lenses...but the crop factor really hurts users who shoot wide angle.