Posted by Randy Wilson on July 2, 2010 at 12:57 PM
Since lens markings on a zoom lens aren't of much use in determining depth of field or hyperfocal distance, I expect most of us use DOF tables or a DOF wheel. However, this approach requires that we be able to measure or estimate distances to various objects in the field of view. I'm probably not much good at estimating distances, and anyhow that strikes me as a very unreliable way to get good results. I've got a little antique optical rangefinder that I've used to measure distances, but I wonder if anyone has tried using a construction or other kind of laser rangefinder, and whether that has worked out for anyone.
I have older lenses which I still use and the DOF scale is readeable on the lens.
The newer lenses I don't have that feature and I don't use a wheel yet.
I use DOF preview, take a shot and magnify it in the camera to check out the results. I guess for most landscape photography this primitive method works but a purist might do it with the wheel, etc.
I have a laser ranger finder but points of interest are usually close stuff that needs initial attention. By that I'm talking down to 9", the out to infinity... A range finder does not seem applicable.
If memory serves DOF it is about 1/3 near and 2/3 distant of the focal point. This has something to do with the "circle of confusion".
Anyway, I'm at the limits and over my knowledge base so will wait for others to comment.
I will be going to Bass Pro next weekend to check them out. I have used a golf rangefinder many times and they work very well on the flags that have special devices on them. I want to see how they work on wildlife and for landscapes.
Posted by Randy Wilson on July 9, 2010 at 11:13 AM
I'd like to hear what you find out, Larry. I may end up buying and testing something like this, which is supposed to be able to measure distances from two inches to 130 ft., a range that would be well-suited to most landscape photography. My biggest concern is that it might not do as well bouncing off leaves on a tree as it seems to do reflecting off an interior wall, which is its intended use.
One issue you guys might run into is that the manufacture of most lenses these days is so sloppy that if there is a scale on the lens at all it probably is not too accurate anyway. Most modern lenses only have a few distance markings on them so you would be guessing where to put the focus point for a given distance anyway (an example is a wide-angle lens - there is no mark between 10 feet and infinity on one of mine - so if the rangefinder says 57 feet, where do you put the focus mark? See what I mean.).
The best and most accurate way to deal with this is to put an autofocus point on the item that you want in focus and go from there - no other plane in front of or behind that point will be in perfect focus anyway, only varying degrees of being out of focus no matter how much you stop down, but that would give you the best chance. Of course, that would only work if your lens, sensor, and camera body were all precise and in perfect alignment, and these days very few are. Bottom line - probably not worth all the trouble - use autofocus, focus confirmation for manual focus, or just make your best guess, stop down, and shoot.
Thanks Tim. I primarily want the rangefinder to obtain distances at which I am photographing wildlife. Seems like folks want to know "how far away were you?".
Thanks for the reply, Tim. I know your approach works because I've seen the results, and I can't argue with success, but I'm just afraid that my best guess won't be nearly as good as yours, although in a lot of situations I do rely on a sense of what's possible that I've developed over the years. My aim, though, is to have a systematic, reliable, and precise technique at hand, especially for tough situations or situations where I don't have enough experience to have a good sense of how far I need to stop down or where I need to focus to get everything at an acceptable level of focus, or in other words, when I just don't have a clue (which is more often than I'd like to admit).
For example, one situation I haven't had a lot of experience with in the past that I'm doing more of lately is shooting night exposures at wider apertures, where there isn't much room for error. Another example might be a shot at something like 45mm, 10' near distance and 75' far distance, which is a situation that sitting here I wouldn't have any idea how to handle.
The approach that I've taken to getting the hyperfocal distance doesn't involve lens markings, but usually goes something like this:
1. find the nearest object in the frame
2. estimate the distance to the nearest object
3. double that distance, then using hyperfocal tables or some other DOF device, find the largest aperture for which that doubled distance is a hyperfocal distance given the current focal length of the lens.
4. if I can still keep the aperture at f/11 or larger, stop down a stop or two from the aperture found in step three
5. focus on something at the doubled distance mentioned in step three
6. shoot
If the shot I'm setting up doesn't need hyperfocal, for instance if the farthest distance is 50 or 100 feet or less, the method is slightly different but similar.
So, where the method can break down most readily is estimating the distance to objects in the frame, which is where I hope a measuring device will come in handy.
I know it sounds slow, cumbersome, and complicated, but it's not once you get used to it, and quite often I kind of abbreviate the process some, since I know that in most situations my best shot at getting acceptable focus everywhere is to focus at a distance double the distance to the nearest object in the frame, and then set an aperture that's small enough to make that distance hyperfocal for the focal length I'm at. For wider focal lengths I know I've usually got a lot of room to spare and have a fairly good sense of what I can get away with.
Posted by Larry Daniel on July 10, 2010 at 6:17 PM
Stopped in today at Bass Pro, found one I liked and had them hold it for until tomorrow night as they have 3X rewards points tomorrow night. Will post what I ended up with when I get it home tomorrow.
I went to bass pro or cabela's and got a hunting laser rangefinder that works pretty well for me. It has a viewfinder with a crosshair to pick your tree or whatever. I use a technical camera which has no focus or framing capability and the laser has been very valuable for longer focal lengths.
Shooting wide angle I use DOF calculations exclusively and have a small tape measure. With a 24mm (about 12mm in 35mm) everything from 1.5' to infiniti is in focus at f/11, 35mm from 4' to Infiniti at f/11.
Posted by Larry Daniel on July 27, 2010 at 3:45 PM
Sorry for being so late getting back to the forum with the rangefinder info. I ended up with the Leupold RX-1000 TBR Compact Digital Laser Rangefinder. One thing I really liked about it was that the read out is red instead of the gray in most of them. It works very well even in low light.
Discussion
10 repliesThe newer lenses I don't have that feature and I don't use a wheel yet.
I use DOF preview, take a shot and magnify it in the camera to check out the results. I guess for most landscape photography this primitive method works but a purist might do it with the wheel, etc.
I have a laser ranger finder but points of interest are usually close stuff that needs initial attention. By that I'm talking down to 9", the out to infinity... A range finder does not seem applicable.
If memory serves DOF it is about 1/3 near and 2/3 distant of the focal point. This has something to do with the "circle of confusion".
Anyway, I'm at the limits and over my knowledge base so will wait for others to comment.
the fisch
The best and most accurate way to deal with this is to put an autofocus point on the item that you want in focus and go from there - no other plane in front of or behind that point will be in perfect focus anyway, only varying degrees of being out of focus no matter how much you stop down, but that would give you the best chance. Of course, that would only work if your lens, sensor, and camera body were all precise and in perfect alignment, and these days very few are. Bottom line - probably not worth all the trouble - use autofocus, focus confirmation for manual focus, or just make your best guess, stop down, and shoot.
For example, one situation I haven't had a lot of experience with in the past that I'm doing more of lately is shooting night exposures at wider apertures, where there isn't much room for error. Another example might be a shot at something like 45mm, 10' near distance and 75' far distance, which is a situation that sitting here I wouldn't have any idea how to handle.
The approach that I've taken to getting the hyperfocal distance doesn't involve lens markings, but usually goes something like this:
1. find the nearest object in the frame
2. estimate the distance to the nearest object
3. double that distance, then using hyperfocal tables or some other DOF device, find the largest aperture for which that doubled distance is a hyperfocal distance given the current focal length of the lens.
4. if I can still keep the aperture at f/11 or larger, stop down a stop or two from the aperture found in step three
5. focus on something at the doubled distance mentioned in step three
6. shoot
If the shot I'm setting up doesn't need hyperfocal, for instance if the farthest distance is 50 or 100 feet or less, the method is slightly different but similar.
So, where the method can break down most readily is estimating the distance to objects in the frame, which is where I hope a measuring device will come in handy.
I know it sounds slow, cumbersome, and complicated, but it's not once you get used to it, and quite often I kind of abbreviate the process some, since I know that in most situations my best shot at getting acceptable focus everywhere is to focus at a distance double the distance to the nearest object in the frame, and then set an aperture that's small enough to make that distance hyperfocal for the focal length I'm at. For wider focal lengths I know I've usually got a lot of room to spare and have a fairly good sense of what I can get away with.
Shooting wide angle I use DOF calculations exclusively and have a small tape measure. With a 24mm (about 12mm in 35mm) everything from 1.5' to infiniti is in focus at f/11, 35mm from 4' to Infiniti at f/11.