Lenses behave like lenses regardless of what camera they are mounted on, their characteristics, depths of field, etc don't change. A 24-105L lens is still the same length on a crop camera.
What changes is the amount of the field of that lens seen by the sensor (the crop seeing proportionately less, obviously). This means that in order to photograph the same subject at the SAME SIZE in the viewfinder with both a full frame camera and a crop camera (using THE SAME lens), you will be proportionately further away from that subject on a crop camera, which means you will have the benefit (or handicap depending on your desires) of a greater depth of field, as the further you get away from a subject the larger the depth of field becomes.
There is a small variation due to the relative size of the pixels in the two types of camera, but for the purposes of a simple explation you can disregard it.
A great example michael49, thank you! What's most notable to me is in the top photo (equal apertures) is not only is the DOF more shallow on the 5D shot, but the OOF areas are "more OOF". More blur.... Thanks again,
ChrisDM wrote:
A great example michael49, thank you! What's most notable to me is in the top photo (equal apertures) is not only is the DOF more shallow on the 5D shot, but the OOF areas are "more OOF". More blur.... Thanks again,
Chris M
www.imagineimagery.com
No, not a great example in my opinion. Apples to oranges...50mm to 85mm. Those lenses are going to have different characteristics. Compare with the same lens on each camera, "zooming with your feet" to maintain the same field of view. Then compare shots from the same distance with the FF image cropped to the same FOV digitally.
Like many things, it depends on the situation. If you use the same lens, at the same distance from the subject, then the FF camera will have the greatest DOF. If you use the same lens, but adjust the distance so that the FF and crop images have the same FOV, then the crop camera will have the greatest DOF.
PhotosByRDD wrote:
No, not a great example in my opinion. Apples to oranges...50mm to 85mm. Those lenses are going to have different characteristics. Compare with the same lens on each camera, "zooming with your feet" to maintain the same field of view. Then compare shots from the same distance with the FF image cropped to the same FOV digitally.
But is that how you photograph? I think most of us, at least when we have the chance, choose our position to get a certain perspective and relationship of objects in the frame, and from there we choose a focal length to give the angle of view that includes only the things we want to show. I think the example is well done and 100% appropriate.
Another way to look at it is that FF is a larger format than 1.6 crop. Sure, it's "apples to oranges" to compare them, but isn't it perfectly valid to say that 4x5 film has less DOF than 35mm film? If you set up the same scene with different formats, you end up using different lenses to get the same photo. If you want the same DOF, you have to compensate with the f/stop. Compare digicams to SLRs for a more contemporary example.
Lenses behave like lenses regardless of what camera they are mounted on, their characteristics, depths of field, etc don't change. A 24-105L lens is still the same length on a crop camera.
What changes is the amount of the field of that lens seen by the sensor (the crop seeing proportionately less, obviously). This means that in order to photograph the same subject at the SAME SIZE in the viewfinder with both a full frame camera and a crop camera (using THE SAME lens), you will be proportionately further away from that subject on a crop camera, which means you will have the benefit (or handicap depending on your desires) of a greater depth of field, as the further you get away from a subject the larger the depth of field becomes.
There is a small variation due to the relative size of the pixels in the two types of camera, but for the purposes of a simple explation you can disregard it.
DOF is determined by three things, and three things only:
1) Lens focal length
2) Aperture used
3) Distance to subject (focus distance)
Notice that sensor size is not included in the three DOF determinants.
Notice that sensor size is not included in the three DOF determinants.
Notice that sensor size is not included in the three DOF determinants.
No, not a great example in my opinion. Apples to oranges...50mm to 85mm. Those lenses are going to have different characteristics. Compare with the same lens on each camera, "zooming with your feet" to maintain the same field of view. Then compare shots from the same distance with the FF image cropped to the same FOV digitally.
6 of one, 1/2 dozen of the other.
One way or the other, it is the photographer's actions that ultimately make the DOF difference. With FF, we either move closer or we increase the focal length in order to maintain the same framing that would suit our style.
The DOF of the lens does not change when you stick it on a different camera. The geeks are correct there. But they always forget the most important part of the formula; the photographer.
Mike Mahoney wrote:
DOF is determined by three things, and three things only:
1) Lens focal length
2) Aperture used
3) Distance to subject (focus distance)
Notice that sensor size is not included in the three DOF determinants.
Notice that sensor size is not included in the three DOF determinants.
Notice that sensor size is not included in the three DOF determinants.
Repeat as often as required for it to sink in.
The sensor size, since it determines FOV, directly affects the photographer's actions when framing a subject. As I just explained, in order to shoot "the same shot" the photographer either increases focal length or moves closer to the subject, both of which decrease the DOF of the shot.
So, indirectly, sensor size affects DOF.
Anyone who can still argue this point is a gearhead who is forgetting the most important part of photography; You.
cogitech wrote:
The geeks are correct there. But they always forget the most important part of the formula; the photographer.
Exactly .. in the hands of a skilled photographer with an adequate assortment of lenses DOF can be created pretty much the same regardless of the sensor size.
And the shooters style is often ignored in these discussions .. some prefer to be closer to their subjects while shooting but still maintain a shallow DOF.
Regardless of how skilled a photographer is, they have a style (good or bad).
When switching from a crop camera to a FF camera, the photographer's style does not change (good or bad). What happens is they shoot just as they did before. They frame things in exactly the same manner. In order to do so, they either move close or increase their focal length. It really is as simple as that and that is why everyone immediately notices a difference when they buy a FF camera.
