is the 10D "multiplier" really just a crop?

[gordeaux]

After 6 months shooting with my 10D, I've come up with a theory. See if there's anything to this:

The "multiplier" effect with my 10D is actually simply a "crop". The sensor is throwing away everything around the outer 40% that the lens is doing, therefore my 400mm lens acts like a 640mm.

If I'm shooting at 400mm at something that only uses 1/2 the frame (a bird in the distance), upgrading to a 1.0 multiplier won't give me any more information on the item I'm shooting, rather it would only fill 1/4 of the frame.

Am I thinking about this right? Or would my 400mm lens give me a better picture on the 1.0 multiplier camera?

Is "multiplier" the marketing department's code word for what the engineers called "crop"? :?

[Canuck]

After 6 months shooting with my 10D, I've come up with a theory. See if there's anything to this:

The "multiplier" effect with my 10D is actually simply a "crop". The sensor is throwing away everything around the outer 40% that the lens is doing, therefore my 400mm lens acts like a 640mm.

If I'm shooting at 400mm at something that only uses 1/2 the frame (a bird in the distance), upgrading to a 1.0 multiplier won't give me any more information on the item I'm shooting, rather it would only fill 1/4 of the frame.

Am I thinking about this right? Or would my 400mm lens give me a better picture on the 1.0 multiplier camera?

Is "multiplier" the marketing department's code word for what the engineers called "crop"? :?

More or less you are spot on.

[Belmondo]

Am I thinking about this right? Or would my 400mm lens give me a better picture on the 1.0 multiplier camera?


It wouldn't be any better. There'd just be more of it.

[Jim Larson]

Spot on.

A 1.6 FOV is only using PART of the standard 35mm frame.

The advantage of full frame photography is merely depth of field control.

A 50mm on a 10D has a depth of field of "X". A 50 mm on a full frame 1D . . has the SAME depth of field. Let's take a real world situation:

A portrait. On a 1Ds you use a 80. On a 10D you use a 50 to get the same framine. Fundamentally, for the same aperature the 80mm lens will have a shallower depth of field. . which many dSLR shooters value.

Take an extreme case. A P&S digicam. For a portrait, because the sensor is SO small, you have a 15mm lens. Depth of field is HUGE. Portraits therefore have no background blur.

Now for the tough confusing part: Depth of field and bokeh are functions of "circle of confusion". These terms relate to the resolving power of the "system". With "L" glass, the sensor is usually the limiting component. OK: Here is the punchline: A full frame 6mp sensor has bigger pixels than a 6mp 1.6 fov camera (same number of pixels in a smaller space). The cropped camera will technically have higher resolving power and a smaller circle of confusion. This shrinks depth of field (assuming you are not limited by a printer or monitor).

Adding to confusion: Bigger pixels (like comparing a 1D to a 10D) will result in higher quality pixels and better color rendition.

Bah: Bottom line: Learn your tools. Understand how aperature affects depth of field for you camera and your style of shooting. The 10D is a great camera.

[Morden]

"is the 10D "multiplier" really just a crop?"

Yes.

[defordphoto]

Instead of looking at it like you're not using all of your lens, I look at it like I'm shooting the sweet spot of all my lenses. All lenses show weaknesses of some sort at the edges. Shooting the 1.6 crop, you avoid those edges and NEVER see those defects.

Bonus!

[Morden]

I look at it like I'm shooting the sweet spot of all my lenses.

A good point. Also avoids vignettting on particularly wide lenses.

[Andy_T]

A good point. Also avoids vignettting on particularly wide lenses.

That's right.

But that's also because the lens isn't wide any more :x

Regards,
Andy

[Morden]

But that's also because the lens isn't wide any more

Indeed; the 16-35 doesn't give nearly so great a field of view on my 10D. :(

[Jim Larson]

Instead of looking at it like you're not using all of your lens, I look at it like I'm shooting the sweet spot of all my lenses. All lenses show weaknesses of some sort at the edges. Shooting the 1.6 crop, you avoid those edges and NEVER see those defects.

Bonus!

Unless you are using a EF-S lens.

An EF-S lens is sized for a cropped sensor. You do use the edges of the 18-55. And those edges are horrible, judging from the resolution tests that I have seen.

(don't get me wrong: For $100 this is a nice lens. . you just do *not* get good wide open edge performance from a $100 lens).