ef-s lenses

So a 10-22 ef-s on a crop body is 10mm to 22mm, is it actually 10-22? If I modified it to fit on my 1Ds Mark ii(which it is and works great) is it 10-22?
My question is how can it be both focal ranges on a crop and a FF?
I understand the multiplier of the crop sensor but if it supposedly only fits on the crop body shouldn't it be advertised as a 16-35 ef-s for crop body?

Read the Lens FAQ
It's at the top of the forum.

Well the glass still has the said focal length, it just has a different crop factor so you get the equivalent effect of a different focal length on a full size sensor (or 35mm film). It would be misleading to advertise... say a 60mm lens as 90ish mm just because the crop factor. 60mm is 60mm.

I understand the chart and the explanation, but why do we refer to crop bodies as crop bodies and not FF equivalents with proper multiplier?
I just think the lens on the appropriate body should reflect the correct mm focal length for ef-s lenses. A 10-22 on a ff cannot be a 10-22 on crop body.
Is 10mm truly 10 mm on a crop body, if it is an EF-S lens?
If that is a true statement would I divide by 1.6 to mount the same EF-S lens to a FF.

Emiliosunshine wrote in post #8377534
I understand the chart and the explanation, but why do we refer to crop bodies as crop bodies and not FF equivalents with proper multiplier?
I just think the lens on the appropriate body should reflect the correct mm focal length for ef-s lenses. A 10-22 on a ff cannot be a 10-22 on crop body.
Is 10mm truly 10 mm on a crop body, if it is an EF-S lens?
If that is a true statement would I divide by 1.6 to mount the same EF-S lens to a FF.

Focal length and field of view are not the same thing.

A 200 mm focal length lens on either body is still 200 mm, but how much you can see is different.

There is no "correct mm focal length" other than that of the glass. It is completely independent of what crop size the sensor is. The focal length is a property of the lens - we derive meaning from it in terms of sensor size, etc - but that is just a product of the camera body design.

If you want a standardized way of describing the effect of focal length on different crop sizes, it would make more sense to describe the fov imo. But the focal length in both cases is the same.

Emiliosunshine wrote in post #8377534
I understand the chart and the explanation, but why do we refer to crop bodies as crop bodies and not FF equivalents with proper multiplier?
.

Same reason medium and large format lenses list their actual focal lengths and not the 35mm equivalent. It is not a 16-35mm lens, it is a 10-22mm lens that may provide a different angle of view depending on what it gets mounted to.

And regardless, Wouldn't it be a hell of a lot more confusing if some lenses were printed with equivalents (EF-S) and others with actual focal lengths? Then how would you know whether to apply a crop factor or if it has already been applied, or if this lens is the same angles of view as that lens, etc, etc. It is easier if all lenses are consistent.

Emiliosunshine wrote in post #8377534
I understand the chart and the explanation, but why do we refer to crop bodies as crop bodies and not FF equivalents with proper multiplier?
I just think the lens on the appropriate body should reflect the correct mm focal length for ef-s lenses. A 10-22 on a ff cannot be a 10-22 on crop body.
Is 10mm truly 10 mm on a crop body, if it is an EF-S lens?
If that is a true statement would I divide by 1.6 to mount the same EF-S lens to a FF.

Do you think all that crazy math should be done for other format cameras such as the many different medium format sizes, large format cameras, etc.? No math is required for any focal length.

Focal length is focal length is focal length. Focal length of any particular lens does not change when you put it on different format cameras.

The 35mm film format (24mm by 36mm) is not, never has been, and never will be the master camera format against which all other formats are measured.

The user of ANY camera should understand what the "normal" focal length for that camera's format (size of film frame or digital sensor) is and that should be the basis for choosing other focal lengths for specific needs.

It's simple. An EF-S 10-22mm lens will give you the same FOV as an EF 16-35mm lens on a 35mm full frame camera. That is all. All the properties associated with a specific focal length lens will stay the same no matter what body it is on.

Look at a point and shoot, the lens focal range is like 4-20mm, yet it still gives a field of view similar to a mid zoom on a 35mm camera. As was mentioned with Medium and Large Format cameras, the lens focal length is still the lens focal length, but to get a "normal" field of view (50mm on FF) you need something like 150mm on Large Format.

It just so happens that 35mm was the most popular format for amateurs for 30 years, and they make "full frame" digital cameras that accept the older film lenses. If you've never used a 35mm film or FF digital camera, the focal length should have no preconcieved filed of view.

Not to mention, if you modified the 10-22mm for use on a 5D/1D, you'd get heavy, heavy vinetteing. The image circle produced by the EF-S lenses is quite a bit smaller than the one produced by an EF lens.

Maybe what's in my mind is not transferring to my keyboard. Is the FOV manipulated in an EF-S lens to simulate the same FOV in a FF with an EF lens? They make the EF-S lens to accomadate the smaller sensor,right? Only the smaller sensor? So will the image on my screen(pixel for pixel) be the same at say 24mm EF-S on 1.6 and 24 mm EF . Providing both cameras had same pixel count.

Emiliosunshine wrote in post #8377711
Maybe what's in my mind is not transferring to my keyboard. Is the FOV manipulated in an EF-S lens to simulate the same FOV in a FF with an EF lens? They make the EF-S lens to accomadate the smaller sensor,right? Only the smaller sensor? So will the image on my screen(pixel for pixel) be the same at say 24mm EF-S on 1.6 and 24 mm EF . Providing both cameras had same pixel count.

EFS covers a smaller image circle, which is large enough to cover the 15mm x 22mm APS-C, but not much larger (FF is too large and would have dark areas in the captured image!)

Emiliosunshine wrote in post #8377711
Maybe what's in my mind is not transferring to my keyboard. Is the FOV manipulated in an EF-S lens to simulate the same FOV in a FF with an EF lens? They make the EF-S lens to accomadate the smaller sensor,right? Only the smaller sensor? So will the image on my screen(pixel for pixel) be the same at say 24mm EF-S on 1.6 and 24 mm EF . Providing both cameras had same pixel count.

i think you're confused....24mm EF-S or EF lens on a 1.6 crop will give the same view... the EF-S just denotes it's made for crops only because it's made for the smaller image circle...

the 24mm on a 1.6 gives the fov of a 38mm lens on a FF

this might help you out http://lens-reviews.com …w-Visualisation-Tool.html

here's an illustration by wilt^ from another thread: https://photography-on-the.net …hp?p=8365739&po​stcount=10

Emiliosunshine wrote in post #8377534
I understand the chart and the explanation, but why do we refer to crop bodies as crop bodies and not FF equivalents with proper multiplier?
I just think the lens on the appropriate body should reflect the correct mm focal length for ef-s lenses. A 10-22 on a ff cannot be a 10-22 on crop body.
Is 10mm truly 10 mm on a crop body, if it is an EF-S lens?
If that is a true statement would I divide by 1.6 to mount the same EF-S lens to a FF.

(ignoring the concept of image circle size for a moment)...
If you use 50mm on 4/3 format, it has a 'tele' FOV because of the 12x18mm frame.
If you use 50mm on APS-C, it has a 'short tele' FOV because of the 15x22mm frame.
If you use 50mm on FF, it has a 'normal' FOV because of the 24x36mm frame.
If you use 50mm on 645, it has a 'wide' FOV because of the 42x55mm frame.
If you use 50mm on 6x7, it has a 'very wide' FOV because of the 56x68mm frame.
If you use 50mm on 4x5" sheet film, it has a 'ultra wide' FOV because of the 90x120mm frame.

50mm is 50mm. The size of the film or sensor is what determines the FOV.

Emiliosunshine wrote in post #8377711
Is the FOV manipulated in an EF-S lens to simulate the same FOV in a FF with an EF lens?

No. An EF-S lens dialed in to 50mm will provide precisely the same image in an APS-C camera such as the 50D as an EF 50mm lens (or any EF zoom dialed in to 50mm) would.

Emiliosunshine wrote in post #8377711
They make the EF-S lens to accomadate the smaller sensor,right? Only the smaller sensor?

The EF-S lenses create a cone of light that only covers the smaller sensor and won't cover all of a 35mm film frame. However, the size of a subject element will be the same (at the sensor) for any two lenses (of any design) that have the same focal length.

Emiliosunshine wrote in post #8377711
So will the image on my screen(pixel for pixel) be the same at say 24mm EF-S on 1.6 and 24 mm EF . Providing both cameras had same pixel count.

Yes.

Don't even think two cameras, though. Do the test with a single camera such as the 50D.