Need help focusing in a scene? Critical focusing? Your advice? Technique?

[l2oBiN]

I have noticed that more often than not my negatives are not in focus as i would like them to be. This is esecially true with my 90mm focal lenght. I beleive it might be my technique that needs refinement. I would love to get some step by step advice on how you critically focus a 4x5 camera, and any tips that might help increase the percentage of keepers in focus. =}

Thanx in advance.

[Lachlan 717]

Perhaps detail your issues in some detail.

Is it side-to-side focus issues? Front to rear?

Perhaps post some examples.

[Ben Syverson]

Anytime you change your movements, check and recheck a few areas of the frame with a good high-power loupe.

If you're still having problems with static subjects, it may be your camera. Or your loupe. Or your eyesight.

[Leonard Evens]

One thing you should do is to make sure your standards are parallel when you are not using tilts or swings. If they aren't parallel, that means you have a slight tilt or swing, so the plane of exact focus won't be parallel to that of the film.

Here is how I do that. I turn the tripod so that the standards are horizontal. I then put a small bubble level on the ground glass and adjust things so it is level. I then use a level on the front standard to see if it is also level. I sometimes find it is slightly off, and I fix that. I first noticed this with my 75 mm lens. I think it may be more of a problem with shorter focal length lenses.

[kev curry]

The first thing I would do if you haven't done so already is familiarize yourself with the the article on the home page that explains the ''near far'' method of focusing the view camera.

http://www.largeformatphotography.info/fstop.html

[GPS]

It would also help if you said what camera you use. They all have their quirks.

[Jack Dahlgren]

Placement of the ground glass relative to the film plane is another possible explanation which would fit with the evidence that it is worse withshorter lenses.

[Drew Bedo]

"The Ground Glass Is Truth" Before you trip the shutter re-check the GG. Do it wide open if checking the plane of critical fosus. Do it at stopped down if DOF is the issue. when shooting still lifes or table-top compositions I place a focusing target in the scene to help me out. I move it around in the composition if need be to get it right. A bar code palel works pretty well.

[l2oBiN]

I think, the problem is getting the focus checked once the lens is stopped down!.. Its gets too dim/grainy... So I beleive I need to learn where to place the "open aperture" focus in order to ensure things will be in focus when stopped down... any suggestions.

[Lachlan 717]

Start with a DOF chart.

Even if you don't use this in the field, a 5-minute study of the relative depths of field at each f-stop, and the way the DOF is split in front and behind the focal distance, will pay massive dividends.

Using one in the field will assist you to use the right focal distance to maximise the chances of getting what you want in focus.

In a short period of time, you'll find that you won't need this chart.

[Brian Ellis]

I think, the problem is getting the focus checked once the lens is stopped down!.. Its gets too dim/grainy... So I beleive I need to learn where to place the "open aperture" focus in order to ensure things will be in focus when stopped down... any suggestions.

Do what Kev Curry suggested, spend whatever time it takes to study and understand the two articles by QT Luong that are linked on the home page, one on focusing the view camera, the other on selecting the optimum aperture. If you understand and apply everything in these two articles you'll have no more focusing problems and you'll always have the depth of field you need for the photograph you want to make.

[Peter De Smidt]

Make sure to check that your ground glass is at the plane of sharp focus. This can be off, and it can be quite frustrating.

Unlike some others, I like to look through a low power viewer, maybe 2x, or simply eyeball the focus. You can watch parts go in and out of focus when you adjust, and you can get very close to what a loupe will tell you, while still being able to see what's happening all over the ground glass. You can always finesse the final setting with a loupe.

If you are doing an interior, or someplace fairly dark, you can place a flashlight in the scene at the point you want to focus, or perhaps use a laser pointer to put a dot of light where you want to focus, and focus on that.

Hyperfocal tables can be helpful. You can use them to mark your camera. If the table says focus at so many feet with a 90mm at F22, then place and object at that distance and focus critically on it, not using any movements. Now mark your camera bed. That'll be a good place to start, as long as you're using that F-stop, and it give the depth of field that you'd like. Note that many hyperfocal tables are pretty generous with allowable blur. Stopping down a stop or two often helps.

[Frank Petronio]

The general rule of thumb for normal lenses (not telephotos) is that if you focus on a plane, the depth of field will be about one-third in front of and two-thirds behind the plane you focus on.

Without bothering with tables, I know that shooting wide open with a 150mm lens @f/5.6 means I will only have a few inches of depth of field at 20' away. @ f/16 I have a couple of feet of depth of field, maybe 19-22 feet if I focus at the 20 foot mark. @ f/45 I have probably 12 to infinity @ the 20 mark. Those are just educated guesses.

If you're still having a hard time focusing in bright light, with a dark cloth and loupe, then perhaps the ground glass (and fresnel, if it is mounted) are not positioned in the correct place to match the sheet of film in the holder. There are numerous threads about how to check for this and fix it yourself (or send it off to a technician).

Or maybe you're just doing something else silly, it would be good to work with an experienced photographer if possible.

[ic-racer]

Required reading:
http://www.trenholm.org/hmmerk/FVC161.pdf

[l2oBiN]

Just an observation, but why are you buying more lenses and more stuff if you can't focus your camera?


...???...

[Jack Dahlgren]

...???...

I think he is talking about the thread where you want to buy a longer lens.
If as you state, more often than not, you are not able to focus correctly, it might make sense to work out the focus problem first, unless you want excellently rendered out of focus images.

At least that is how I took his comments.

[Leonard Evens]

The general rule of thumb for normal lenses (not telephotos) is that if you focus on a plane, the depth of field will be about one-third in front of and two-thirds behind the plane you focus on.



I often see comments like this. I am sure it makes sense with appropriate qualifications, but it is obviously not right in all circumstances. For example, if you focus at the hyperfocal distance, the amount in focus behind the focus plane is infinite, which is certainly much greater than twice the amount of focus in front of that plane. Also, for close-ups, the near DOF and the far DOF are approximately equal.

It is not too hard to see that the one circumstance in which the far DOF is twice the near DOF is when you are focusing at one third the hyperfocal distance. So it may be true that the rule is close enough in the near middle distance to be of some use.

Perhaps, someone can explain just what this rule means in an operational sense. It is repeated so often, that it must be useful in some wy. I'd appreciate it greatly if someone would tell me how he/she uses this rule in practice.

[Jack Dahlgren]

I often see comments like this. I am sure it makes sense with appropriate qualifications, but it is obviously not right in all circumstances. For example, if you focus at the hyperfocal distance, the amount in focus behind the focus plane is infinite, which is certainly much greater than twice the amount of focus in front of that plane. Also, for close-ups, the near DOF and the far DOF are approximately equal.

It is not too hard to see that the one circumstance in which the far DOF is twice the near DOF is when you are focusing at one third the hyperfocal distance. So it may be true that the rule is close enough in the near middle distance to be of some use.

Perhaps, someone can explain just what this rule means in an operational sense. It is repeated so often, that it must be useful in some wy. I'd appreciate it greatly if someone would tell me how he/she uses this rule in practice.

The whole point of it is that DOF is asymmetrical from the plane of focus. As you pointed out, the amount of asymmetry is not linear, the example of hyperfocal distance is of course one extreme.

I usually focus by racking in and out and put the focus where I want instead of relying on a rule, so I can't claim to follow this guideline, but I think it is a useful rule of thumb for someone who is both - just getting started, and doesn't want to do any math.

But I suspect your question is driven by the same distrust of "rules of thumb" that I feel. I've come to accept that even if they are not strictly accurate, they are useful for some people some times, and that is enough.

[jim kitchen]

Folks,

A few of you might find that these DOF tables could be interesting, complete with their designated hyperfocal distances, albeit they are Schneider glass charts, which were too readily available from their website... :)

Their website lists many DOF charts, and it is located here: https://www.schneideroptics.com/info/depth_of_field_tables/index.htm

I hope this helps.

jim k

[kev curry]

I'm relieved I discovered the articles written by Rockwell and Luong on how to focus a view camera using the 'near far' method, then took Rockwells advise and went on to make my own paper dial that attach's to the focusing wheel of the camera thats used to quickly determine the optimum aperture for every situation. Once done focusing is accurate, easy, very quick and assured with no fuss, no calculations, no tables, no math, no soar head, no creative suffocation and no guess work...i.e ''need a lot of DOF here, hmm...think I need f45 for this one but I'll use f64 just to be sure''.

[ki6mf]

Carry a small pocket lever, i prefer these over the bubble levers that came on my camera, to check that front standards are level. I measure two directions left/right and front/back to once the shot is framed. This can help make sure you do not have a bit of tilt on one of the standards. Also a pocket level makes you look like a master of the universe. Digital photographers are in more awe, women will love you, and fish will fear you.

[Brian Ellis]

I often see comments like this. I am sure it makes sense with appropriate qualifications, but it is obviously not right in all circumstances. For example, if you focus at the hyperfocal distance, the amount in focus behind the focus plane is infinite, which is certainly much greater than twice the amount of focus in front of that plane. Also, for close-ups, the near DOF and the far DOF are approximately equal.

It is not too hard to see that the one circumstance in which the far DOF is twice the near DOF is when you are focusing at one third the hyperfocal distance. So it may be true that the rule is close enough in the near middle distance to be of some use.

Perhaps, someone can explain just what this rule means in an operational sense. It is repeated so often, that it must be useful in some wy. I'd appreciate it greatly if someone would tell me how he/she uses this rule in practice.

The only benefit I know of is that the 1/3-2/3 "rule" lets someone know that with some lenses under some circumstances the circles of confusion diminish in size quicker in front of a subject than behind it (i.e. there's usually not a linear relationship between the relative size of the circles of confusion in front of and behind the point of focus).

But how one would actually use or apply this "rule" in practice beyond understanding the general point is beyond me. Among other problems, the relative size of the circles of confusion in front of and behind the focus point varies with the focal length of the lens being used and also with the distance from lens to focus point. And since most of us use more than one lens and stand more than one distance from the subject on which we're focusing the variables dwarf the "rule." And even if one thinks the 1/3-2/3 "rule" is a good one and should be used when focusing, there's the problem of figuring out where the 1/3-2/3 dividing line is when you're anywhere except in a studio or some other location where distances can be easily measured.

All in all it's a "rule" that has so many exceptions and is so difficult to actually use with any degree of precision that IMHO it should be ignored once one understands the general point it illustrates.