Differences between Full Frame and APS-C, all of them...

[FocusTester]

I know that when a full frame lens is mounted on an APS-C camera, the focal length should be multiplied by 1.6 to find the full-frame equivalent focal length. Likewise, it is often said that the aperture value should be multiplied by 1.6 as well.

Therefore, a 100/2.8 lens effectively becomes 160/4.2 when mounted on an APS-C camera. I understand this with regard to effective magnification and extension of the depth of field, but is there really a stop of light loss when this lens is used on an APS-C camera. Having the aperture shift from 2.8 to an effective 4.2 would seem to indicate this, but it is hard to believe. After all, the same amount of light is going through the lens.

Maybe the implication is that the 4.2 aperture affects the depth of field only, without there being a stop of light loss. In other words, you still get the speed of a f/2.8 lens but the depth of field of a f/4.2 lens.

Can someone please clarify this.

 

[o hey tyler]

Aperture does not change on aps c bodies. But you won't be as close to the minimum focus distance due to the crop factor.

 

[FocusTester]

Aperture does not change on aps c bodies. But you won't be as close to the minimum focus distance due to the crop factor.

This seems to be in contradiction with everything I've read. See for example the aperture equivalence table which is about 2-3 pages down at the following link:

http://www.dpreview.com/reviews/sony-cybershot-dsc-rx100/

 

[o hey tyler]

This seems to be in contradiction with everything I've read.

Provide sources plox.

 

[JG_Coleman]

APS-C vs full frame - Depth of field comparison | Amateur Photographer

"When an APS-C-format camera is used to record the same composition as a full-frame model, the images from the smaller-format camera have greater depth of field at any given aperture. The properties of the lens and aperture in use don't magically change, but getting the same composition with an APS-C-format camera means that it must either be moved further away from the subject than the full-frame model, or a shorter focal length optic must be used. Both of these factors result in greater depth of field."

I'm not a lens scientist and I don't claim to fully understand the finer points of their workings, but I think the idea of "multiplying aperture by 1.6" refers only to depth-of-field, not actual light-loss.

 

[runnah]

Aperture does not change on aps c bodies. But you won't be as close to the minimum focus distance due to the crop factor.

This seems to be in contradiction with everything I've read.

Aperture relates to the size of the diameter of the iris inside the lens. The lower the number the larger the opening of the iris.

Crop sensors are smaller than a full frame sensor so the focus point of the sensor is different.

 

[astroNikon]

I never understood this either, because on an ad for I think it was a Sigma lens 1.4 Art it started the 1.4 gives it the effective aperture of a FF 2.8 (or something like that).

 

[runnah]

APS-C vs full frame - Depth of field comparison | Amateur Photographer

"When an APS-C-format camera is used to record the same composition as a full-frame model, the images from the smaller-format camera have greater depth of field at any given aperture. The properties of the lens and aperture in use don't magically change, but getting the same composition with an APS-C-format camera means that it must either be moved further away from the subject than the full-frame model, or a shorter focal length optic must be used. Both of these factors result in greater depth of field."

I'm not a lens scientist and I don't claim to fully understand the finer points of their workings, but I think the idea of "multiplying aperture by 1.6" refers only to depth-of-field, not actual light-loss.

That article is very much incorrect.

1.6 refers to the focal distance. So if you have a 50mm on a crop is roughly the same as a 85mm on a FF. The DOF is much shallower on the FF than a crop.

 

[FocusTester]

OK, so is there agreement that the effective change in aperture applies to DOF only and not the amount of light hitting the sensor (i.e., no effect on the shutter speed/ISO settings).

 

[runnah]

OK, so is there agreement that the effective change in aperture applies to DOF only and not the amount of light hitting the sensor (i.e., no effect on the shutter speed/ISO settings).

No. Crop and FF lenses have the same sized aperture opening.

The different is in the focus point.

 

[JG_Coleman]

APS-C vs full frame - Depth of field comparison | Amateur Photographer

"When an APS-C-format camera is used to record the same composition as a full-frame model, the images from the smaller-format camera have greater depth of field at any given aperture. The properties of the lens and aperture in use don't magically change, but getting the same composition with an APS-C-format camera means that it must either be moved further away from the subject than the full-frame model, or a shorter focal length optic must be used. Both of these factors result in greater depth of field."

I'm not a lens scientist and I don't claim to fully understand the finer points of their workings, but I think the idea of "multiplying aperture by 1.6" refers only to depth-of-field, not actual light-loss.

That article is very much incorrect.

1.6 refers to the focal distance. So if you have a 50mm on a crop is roughly the same as a 85mm on a FF. The DOF is much shallower on the FF than a crop.

You misread, I think. Take another look. The article CORRECTLY states that depth-of-field will be greater with the APS-C sensor for the same reason you just stated.

Nobody is arguing that APS-C bodies don't get an effective 1.6x focal length increase. We are discussing how that affects aperture... whether only depth-of-field or also light loss.

The article suggests that the only vaguely aperture-related difference is depth-of-field... exactly what you said.

 

[runnah]

Here is a very scientific comparison I just shot.


Both shot at 50mm, 400 ISO, 1/60 and f/1.8

 

[Derrel]

APS-C vs full frame - Depth of field comparison | Amateur Photographer

I highly doubt that one of the world's most well-established, and most-respected photography magazines has published an article that could by any stretch of the imagination be described as, "very much incorrect." Amateur Photographer is a trusted source, and the article is quite simple in its scope. The depth of field comparison chart is pretty cut-and-dried stuff. It's clear, and we all know this: a smaller capture format gives greater depth of field at each equivalent picture angle.

If you want SHALLOW depth of field images, increasing the film size has long been a simple way to do that. If you want to get deeper, more expansive depth of field images, moving to a SMALLER capture area, like m4/3, brings with it significantly deeper depth of field at every angle of view, from wide, to normal, to telephoto.

One of the REAL secrets of the m4/3 format is that it allows street and social/documentary shooters to create wonderfully in-focus Near/Far juxtapositions that are literally IMPOSSIBLE to make with a medium-format rollfilm camera, and are very difficult to achieve on the older 135 format (aka 24x36, AKA FX in Nikon-speak or FF in Canon-speak).

Because so many people will argue this,. and do not understand this, dPreview for example, has begun listing "depth of field equivalency" figures for the small-sensor digicams, which allow people to see, and to understand, the depth of field equivalence of various f/stops, when lenses are used on very small-format digital cameras, like say the new Sony model that has the 24-200mm equivalent lens angles of view, with a constant f/2.8 aperture across the zoom range.

The word equivalence is a big,big word among the serious smaller-format digital shooters.

 

[JG_Coleman]

In his/her haste to respond, I think runnah has both missed the OPs actual question and simultaneously failed to actually read the article I quoted.

 

[Derrel]

In his/her haste to respond, I think runnah has both missed the OPs actual question and simultaneously failed to actually read the article I quoted.

It would seem so.

HERE is an article filled with example photos, and a chart showing and categorizing different degrees of background blurring, and charting these degrees out as they relate to sensor size.

Background blur and its relationship to sensor size: Digital Photography Review

READING, and understanding this article might help cut through some of the misunderstanding that is so rampant about this topic.

Please people, take a look, and get a grasp.