Tilt in an urban enviroment

[Ben R]

Assuming that I have to use a rather small CoC these urban close up images are going to end up rather difficult, a photo like either of those two will be almost impossible to shoot with front to back DOF given that the nearest point needing to be in focus is approx 1 metre away from me. Certain compositions will work with using a wider lens but the perspective from a wider lens would often be exaggerated with these types of compositions in a detrimental way.

My MPP is arriving on Saturday night, I think next week will involve an interesting amount of time squinting at the GG through a loupe stopped down to f32! Hope my satin snow from the Gandolfi will fit in the MPP.

Can someone and possibly Leonard who seems to have a great grasp on both the mathematics and an ability to explain it to a dufus like me (!) recommend the best way to focus when using a rangefinder or in situations like this where I'm not going to get everything in a perfectly sharp DOF. With 35mm it was a case of about 1/3 of the way into the compostion. With 4X5 I've used the Hansma technique. I know that with LF it is preferrable to focus 1/2 way into the compostion though I don't understand why it is different, would it be better considering that large and close up elements in the composition need to be pin sharp with smaller further away elements not needing as much focus emphasis, the distant stonework in the far rear of either of the compositions on the first page for example to concentrate the focus on the former? Or should I try to achieve a equal sense of DOF albeit not as incredibly sharp as technically possible from the back to the front? In other words, should I focus on the main part/subject of the composition and stop down letting the DOF lead the eye into the photo or given that I do want maximum DOF, try and get everything as sharp as everything else?

The photo below was shot with a 210mm lens on 645 film @ f22. The far background, through the gap, is not pin sharp. All the branches and trees front to back are. The gap at the end isn't soft, not enough to detract but the subject is very sharp as it should be here. I think that this is a good illustration of my question above.

[Donald Miller]

There is another way to accomplish what you want if it is really important to you. When taking a single exposure with extensive front to rear distance, stopping down excessively will eventually degrade the image due to diffraction...so depending on the degree of enlargement, there will be a point at which the lines representing diffraction and depth of field will cross so far as image resolution throughout the image is concerned. Once this point is crossed nothing positive is going to happen.

The other way of doing this is to photograph two or more images at wider apertures focusing each exposure at optimal points in the scene (front to rear). Once done, a person could scan each of the negatives and blend them using one of the software programs that are available. Ptgui would be one such program. Since one is not expecting a single exposure to carry the mail, so to speak, one can utilize the equipment to it's optimal preformance.

This would be the equivalet of HDR blending as applied to image depth of field.

[sanking]

Do I tilt (or swing in the case of the 2nd one?) and stop down for DOF in the verticals assuming that I will have less to stop down and faster exposure time or is this a bad idea for a reason that in my ignorance I am still as yet unaware?

Many thanks for your suggestions.

I tend to use as few movements as possible. In the great majority of scenes, even urban ones, I simply level the tripod, put the camera on the tripod land make sure the back is level and vertical. I use rise or fall to compose the scene, and generally a little tilt to achieve near to far focus, and sometimes a bit of front swing. I then select the best point of focus to achieve maximum depth of field for the aperture, which is generally a point about 1/3 of the way into the field. Tilting or swing the back will distort the scene so I try to avoid this unless for some reason it is necessary.

In your shots I am not bothered by the perspective so I would not have done any more than the minimum I described above, though I would have closed down the lens to f/32 to maximum. Because of diffraction I rarely close down any more than f/32 with 5X7 format.

Some scenes may require more movements than your camera or lens will allow. If so, do as much as possible in the camera, and then scan the negative and complete the job in Photoshop or in whatever image software you have. Because of the large amount of information in film you can do much more extensive perspective control than with a DSLR, which may have only about 1/10 of the total information in the file as in a film scan of the size you are working with.

With regard to your question about the use of a rangefinder, there is not much you can do to control DOP in scenes with very near and very far objects other than focusing on a spot about 1/3 into the field and close down the lens as much as possible. Short focal length lenses help a lot, of course, which is one of the main reason why wide angle and normal focal length lenses are so popular with cameras like the Leica and Mamiya 7II.

Sandy King

[Ben R]

So you say a 1/3 not 1/2?

I had thought of using the rangefinder for the Hansma method, you get the same accuracy but much faster.

My new camera is arriving in about 10 minutes and I'm back in the Old City of Jerusalem tomorrow morning. If I have time I'll do some dry shooting to see what kind of fstops I'm having to resort to and the resulting shutter speeds.

[Ole Tjugen]

Diffraction doesn't really matter so much in LF - at least that's my experience. I've shot at all apertures down to f:90, and if DoF is more important to me than absolute sharpness, that's what I'll do.

I also find a little blur in the foreground less objectionable than a fuzzy background - especially in landscape scenes. So I focus on the furthest point (often the horizon), and stop down until the foreground is acceptable. The results (if I'm lucky) can look like THIS.

After I tried this the first time (the link above), I haven't used the hyperfocal technique.

[sanking]

So you say a 1/3 not 1/2?

I had thought of using the rangefinder for the Hansma method, you get the same accuracy but much faster.

My new camera is arriving in about 10 minutes and I'm back in the Old City of Jerusalem tomorrow morning. If I have time I'll do some dry shooting to see what kind of fstops I'm having to resort to and the resulting shutter speeds.

I generally focus about 1/3 into field, not 1/2. Neither distance is always the best. Whatever figure you use, either 1/3 or 1/2, it will only be absolutely correct at one point between near and far focus, but at no other. A depth of field calculator would help determine the best focus and may be useful for those with limited experience with view camera work. For experienced user, however, use of a depth of field calculator would be just a waste of time, IMO.

Sandy King

[sanking]

Diffraction doesn't really matter so much in LF - at least that's my experience. I've shot at all apertures down to f:90, and if DoF is more important to me than absolute sharpness, that's what I'll do.

I also find a little blur in the foreground less objectionable than a fuzzy background - especially in landscape scenes. So I focus on the furthest point (often the horizon), and stop down until the foreground is acceptable. The results (if I'm lucky) can look like THIS.

After I tried this the first time (the link above), I haven't used the hyperfocal technique.

Diffraction is a pretty big deal if you plan to enlarge very much. At f/90 you are diffraction limited to about 15 lines/mm. That won't give you a critically sharp print at 16X20 size from a 4X5" negative.

If contact printing, I agree with you that DOF is more important than absolute sharpness.

Sandy King