Posted by Andy Brehm on August 24, 2008 at 2:33 PM
So I have been playing around a bit with hyperfocal distances using a CoC of 0.015 around the house to "hone" the method. Something I have found out pretty quick though is there seems to be very little tolerance for error. At one point I pulled out a tape measure to make sure I was getting pretty close to the exact distances instead of just eye-balling it and I found out that I was apparently off enough on measurement that the entire image was unacceptably out of focus.
How do you guys combat this, do you take out tape measures in the field and measure down to the nearest fraction of a foot to make sure you have the distance is spot on? If that is what is required I might just let the AF take over because I'm afraid I will miss too many opportunities measuring out distances when I could be taking pictures! Do you guys have any hints? I know you get better at it with practice, but here at home I was only a few inches off and I don't think I will ever get better than sub-inch estimation in the field.
Also, when you use longer lenses and the hyperfocal distance moves into the 100+ range, how do you deal with this? AF or something else?
Any input appreciated.
Thanks,
andy
Posted by John Mumaw on August 24, 2008 at 5:30 PM
Which lens are you using with your tests?
A wide angle lens seems to be much more forgiving of length discrepancies than does a longer barreled lens like the 24-105 lens.
And yes, a small lightweight tape measure is part of my kit for critical work (e.g. wildflowers in mountain meadows).
Not sure if manual focusing is a requirement here. I use AF all of the time and it seems to work just fine.
As a side note, I'm relying more and more often on the principles of Digital Scheimpflug in order to ensure perfect DOF throughout the image without having to rely upon stopping down to potentially image degrading apertures.
Posted by Paul Gana on August 24, 2008 at 11:48 PM
gee DIGITAL scheimpflug that's interesting, I just learned something new today, too bad I don't have CS3
Posted by Andy Brehm on August 25, 2008 at 12:07 AM
Thanks for the info John, I will have to play around with that technique to see if it helps at all.
As for my tests around the house I have been using th 24-105, but only using it at 24mm. I would assume that would be a reasonable focal length since it is wide angle.
Andy
Posted by Kalin Wilson on August 25, 2008 at 9:55 AM
Andy,
I use the distance guage on my lenses. It's not exact but I take advantage of the fact that if you focus slightly beyond the hyperfocal distance you're still safe. Still it depends on the subject. If I want a foreground object in focus, I'll make sure to get that in focus or adjust my composition to place it inside the hyperfocal distance. If I want the background in focus, I'll focus at infinity. All of the hyperfocal descriptions state that objects at inifinity will be 'acceptably in focus'. It seems to me that focusing at infinity, particularly with longer lenses, yeilds more sharpness at infinity than focusing at the hyperfocal distance. But then you may lose focus on foreground objects - so it's a trade.
Good luck with your experiments!
Posted by Craig Schultz on August 25, 2008 at 6:28 PM
Andy, if you play golf, get a laser rangefinder; they work great to find distances in the field for hyperfocal shooting. Since the distance markings on modern Canon lenses leave a LOT to be desired, I calibrate mine using a tape measure from 1-15ft. I then manually focus the lens for hyperfocal distances out to 15ft and use the rangefinder beyond that.
Sounds like overkill, but I always had DOF issues until I adopted this method. YMMV.
Discussion
5 repliesHow do you guys combat this, do you take out tape measures in the field and measure down to the nearest fraction of a foot to make sure you have the distance is spot on? If that is what is required I might just let the AF take over because I'm afraid I will miss too many opportunities measuring out distances when I could be taking pictures! Do you guys have any hints? I know you get better at it with practice, but here at home I was only a few inches off and I don't think I will ever get better than sub-inch estimation in the field.
Also, when you use longer lenses and the hyperfocal distance moves into the 100+ range, how do you deal with this? AF or something else?
Any input appreciated.
Thanks,
andy
A wide angle lens seems to be much more forgiving of length discrepancies than does a longer barreled lens like the 24-105 lens.
And yes, a small lightweight tape measure is part of my kit for critical work (e.g. wildflowers in mountain meadows).
Not sure if manual focusing is a requirement here. I use AF all of the time and it seems to work just fine.
As a side note, I'm relying more and more often on the principles of Digital Scheimpflug in order to ensure perfect DOF throughout the image without having to rely upon stopping down to potentially image degrading apertures.
As for my tests around the house I have been using th 24-105, but only using it at 24mm. I would assume that would be a reasonable focal length since it is wide angle.
Andy
I use the distance guage on my lenses. It's not exact but I take advantage of the fact that if you focus slightly beyond the hyperfocal distance you're still safe. Still it depends on the subject. If I want a foreground object in focus, I'll make sure to get that in focus or adjust my composition to place it inside the hyperfocal distance. If I want the background in focus, I'll focus at infinity. All of the hyperfocal descriptions state that objects at inifinity will be 'acceptably in focus'. It seems to me that focusing at infinity, particularly with longer lenses, yeilds more sharpness at infinity than focusing at the hyperfocal distance. But then you may lose focus on foreground objects - so it's a trade.
Good luck with your experiments!
Sounds like overkill, but I always had DOF issues until I adopted this method. YMMV.