Depth of Field Mode

[John]

I have encountered two types of depth of field mode on Canon Cameras which operate as follows:-

Type 1. (Found on EOS 30)
1. Place the focus point over the nearest part of the subject to be in focus then press the shutter release half way.
2. Repeat step one with the focus point placed over the farthest point to be in focus.
3. Compose the picture and press the shutter release all the way to take the picture. Job done.

Type 2. (Found on 20D)
1. Set the camera to DOF mode (all nine focus points are active.)
2. Compose the picture so that one focus point is over the nearest point you want in focus and one point is over the most distant point you want in focus.
3. Press the shutter release half way and those focus points which flash are in focus. If you are lucky, or skillful, the two important ones will be amongst those which flash
4. Press the shutter release all the way to take the picture.

I very much prefer type one, it is much quicker and less restrictive, so I cannot understand why Canon have gone for type 2 on the 20D. What do other members think?

It may be that I am not using type 2 correctly and if so, I should be grateful if someone would point me in the right direction.

John

[Don Hoey]

John,

I don't have a Canon camera so can only offer an outsiders view.

The march of technology. I don't have any such option so end up estimating the best point of focus, and dof scales on modern lenses are not a patch on my old M/F lenses.

If I have interpreted your post correctly Type 2 will show in the flashing points if there is sufficient dof and therefore indicate if there is not. Whereas in Type 1 there appears the possibility of point of focus being selected at a compromise point if insufficient available dof and you would be non the wiser until the image is checked.

I think your preference for Type 1 is due to your familiarity with it and confidence in the results you get. If I had the option of either, then based on your descriptions I would go for Type 2.

Don

[Gidders]

Originally Posted by John

Type 2. (Found on 20D)
.... If you are lucky, or skillful, the two important ones will be amongst those which flash

My interpretation of the instruction manual is that the camera will select the apeture so that the DoF is sufficient so that the area covered by the focus indicators is sharp (and it seems to work on the odd occasion that I've tried it). This is always supposing that the range of adjustment of the lens/shutters speed is capable of doing so and delivering a correct exposure for the given ISO. It should be a 1 press ( 2 x 1/2 press I suppose) job with the camera doing the hard work and enabling the less lucky/skillful to achieve sharpness from front to back

[John]

Originally Posted by Don Hoey

John,

I don't have a Canon camera so can only offer an outsiders view.

The march of technology. I don't have any such option so end up estimating the best point of focus, and dof scales on modern lenses are not a patch on my old M/F lenses.

If I have interpreted your post correctly Type 2 will show in the flashing points if there is sufficient dof and therefore indicate if there is not. Whereas in Type 1 there appears the possibility of point of focus being selected at a compromise point if insufficient available dof and you would be non the wiser until the image is checked.

I think your preference for Type 1 is due to your familiarity with it and confidence in the results you get. If I had the option of either, then based on your descriptions I would go for Type 2.

Don

Don,
You maybe right: you would be right if I had the Canon model which has 35 focus points. When using type 1, if there is insufficient DOF the aperture flashes. Thank you for your opinion which I value.

John

[John]

Originally Posted by Gidders

My interpretation of the instruction manual is that the camera will select the apeture so that the DoF is sufficient so that the area covered by the focus indicators is sharp (and it seems to work on the odd occasion that I've tried it). This is always supposing that the range of adjustment of the lens/shutters speed is capable of doing so and delivering a correct exposure for the given ISO. It should be a 1 press ( 2 x 1/2 press I suppose) job with the camera doing the hard work and enabling the less lucky/skillful to achieve sharpness from front to back

Yes the area covered by the flashing points is in focus, but what if that is not the area you want? For example what if you want everything from 6feet to infinity to be in focus but the bottom focus point covers something 30 feet away. With type 1 you get the area you want or a flashing aperture value to tell that what you want is impossible. Thank you for you reply which I will keep thinking about.

John

[Tannin]

I haven't really got to gips with depth of field mode on the 20D. I used it a little when I first got the camera, but not at all since then. I just set the ISO as high as I dare and stop it down as far as I can (given the available light), focus on an object that I guess is about the right distance away, and press the shutter. (Sometimes I bracket focus.)

It sounds like a very hit-or-miss method and ... guesss what .... the results are very hit or miss. Sometimmes I get a good result, sometimes it's a bin job. I sometimes wonder if I need to take the time to get more scientific about it, other times I think it's just a matter of developing an eye for it as my experience builds up. Perhaps the correct answer is a little of both.

I often toy with the idea of getting a tilt-shift lens, but I'm afraid that the reality is that I'm not good enough to get full advantage from the lenses I already have, so maybe buying yet another one is a little pointless at this stage.

Besides, by the time you combine modern 1.6 crop viewfinders (less light on the mirror = less clarity through the viewfinder than the old film cameras) with these stupid ground glass focus screens you get these days (whatever happened to the wonderful old split image screen?) it's very hard to be sure you are getting a good manual focus. Maybe I should get one of those third-party focusing screens.

(Oh, I have an angle finder, which is supposed to help, but don't seem to use it much. Maybe when the spring arrives and the wildflower season starts.)

[John]

Originally Posted by Tannin

I haven't really got to gips with depth of field mode on the 20D. I used it a little when I first got the camera, but not at all since then. I just set the ISO as high as I dare and stop it down as far as I can (given the available light), focus on an object that I guess is about the right distance away, and press the shutter. (Sometimes I bracket focus.)

It sounds like a very hit-or-miss method and ... guesss what .... the results are very hit or miss. Sometimmes I get a good result, sometimes it's a bin job. I sometimes wonder if I need to take the time to get more scientific about it, other times I think it's just a matter of developing an eye for it as my experience builds up. Perhaps the correct answer is a little of both.

I often toy with the idea of getting a tilt-shift lens, but I'm afraid that the reality is that I'm not good enough to get full advantage from the lenses I already have, so maybe buying yet another one is a little pointless at this stage.

Besides, by the time you combine modern 1.6 crop viewfinders (less light on the mirror = less clarity through the viewfinder than the old film cameras) with these stupid ground glass focus screens you get these days (whatever happened to the wonderful old split image screen?) it's very hard to be sure you are getting a good manual focus. Maybe I should get one of those third-party focusing screens.

(Oh, I have an angle finder, which is supposed to help, but don't seem to use it much. Maybe when the spring arrives and the wildflower season starts.)

Thank you Tannin.

John