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Nikon hyperfocal questions for Joe Petrik

guybat

guybat

[+]
On my Nikkor 24mm f/2.8, there are some hyperfocal measuring lines just below the distance window marked f22, f16 & f11. There's also an unmarked round dot in between the f11 and the centre line that I've seen on other Nikkor lenses - is this for f8?

Do you use the centre of the infinity symbol to line up with these markings?

Hyperfocal for my lens at f11 is 8.43ft (from the Nikonians calculator), which doesn't exactly match up to the marked f11 line - is this because the markings on Nikon lenses are for 35mm rather than digital?
 
guybat,

I assume you have the 24mm AF-Nikkor, since the MF version has a one more hyperfocal mark. Does it look like this?

afd2428.jpg


Or this?

ais2428.jpg


With hyper focusing, you have a range of distances that are in acceptable focus at a given f-stop. Set the lens to whatever f-stop you desire, then turn the focusing ring until the min and max distances you want in focus are between the markings for that f-stop. As you know, the smaller the aperture, the greater the range of distances that are hyperfocused.

At very close distances, you may may get only a few centimetres of range that are in acceptable focus. But at more typical distances, you may get everything from, say, a metre to optical infinity in acceptable focus, depending on f-stop obviously.

There's also an unmarked round dot in between the f11 and the centre line that I've seen on other Nikkor lenses - is this for f8?
Click to expand...
No, that's the focus mark for infrared focusing if you use IR film or a digital camera that's sensitive to IR. Unless you're into really ****y photography, just ignore that dot.

Joe
 
Thanks Joe - it is indeed the AF-D. I shall ignore the ****y dot as instructed.
I'm using f11 nearly all the time with a tripod , and getting pretty consistent results.

I still can't quite work out if as I said dSLRs have a slightly different hyperfocal to 35mm film cameras.
 
guybat,

I'm using f11 nearly all the time with a tripod , and getting pretty consistent results.
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With the 24mm, f/11 will give you a ton of depth of field. Everything from about a metre to optical infinity will be in focus, which ought to cover just about every picture, apart from close-ups.

Incidentally, at f/22 my ultrawide-angle lens gets everything from a foot to optical infinity in decent focus, becoming, essentially, a focus-free lens.



I still can't quite work out if as I said dSLRs have a slightly different hyperfocal to 35mm film cameras.
Click to expand...
It shouldn't. All that changes with the smaller-than-film sensors in a D-SLR relative to a 35mm film camera is the lens's angle of view, not its focusing or hyperfocal range.

Joe
 
I was just puzzled that the online DOF calculators I've found at Nikonians and http://www.dofmaster.com/dofjs.html seem to give different hyperfocal values for the D50 and for 35mm. But if you reckon it should be the same, I'm happy just to use the DOF markings on the lens. As you say, there's a pretty big margin of error anyway.
 
guybat,

I was just puzzled that the online DOF calculators I've found at Nikonians and http://www.dofmaster.com/dofjs.html seem to give different hyperfocal values for the D50 and for 35mm.
Click to expand...
It has to do with something called the circle of confusion, which depends on the film/CCD size, something that has always confused me. I'll see if I can find a more satisfying answer, but in practice I think you'll find that a 24mm lens at f/11 give lots of depth of field.

Joe
 
guybat,

The circle of confusion, somewhat less confusing than usual --

http://en.wikipedia.org/wiki/Circle_of_confusion

http://www.luminous-landscape.com/tutorials/understanding-series/dof.shtml

From the Luminous Landscape
"There was a query in October, 2001 on my Discussion Forum as to whether Depth of Field was calculated any differently for digital Vs. film. The answer is, no. There is no difference whosesoever. DOF doesn't care about the recording media type or size, though a lower COF is used for medium and large format, since the amount of magnification to make a decent sized print is much less than for 35mm."
Click to expand...

To be honest, I'm still kinda confused about the COF, so it appears it's aptly named.

Joe
 
Confused? Me too.

Looking at the maths behind the online DOF calculators, it seems that it's the COF that is the factor behind the difference between say a 35mm and a dSLR hyperfocal distance. But on the basis of the above links, final print size could be just as valid a variant as sensor size in calculating COF.

Whatever. I'll stick to the markings on the lens for now.
 
guybat,

Man, this is getting complicated. When I take a picture I don't know what the final outcome will be -- a print (what size), projected on screen (viewed from what distance), or looked at briefly on my computer monitor (at what magnification in PS) -- until long after the shutter is tripped.

Don't know about you, but I'm sticking to the markings on the lens for now.

Joe
 
Why not just stop down the lens to the intended aperture and see the DOF via the viewfinder? Too simplistic or too dark?

James
 
You really can't see a damn thing through a Nikon D50 (or any other) digital SLR's viewfinder, so manual focusing is pretty much guesswork. I'm just hoping when I get my next dSLR in a few years time, they'll have realised people actually want to be able to see what they're focusing on, and fit proper 100% viewfinders.
 
My Pentax *ist DS viewfinder is pretty bright. I routinely focus manually, aperture fully open, with lenses up to f4 with little trouble, then stopping down to check that the DOF is acceptable before firing off the shot. A dark viewfinder was one of three reasons I didn't buy a Nikon D70 instead.

James
 
Yes, the original *ist DS is supposed to have the only decent view finder around among dSLRs - at the time though, it was a lot more than the D50. In 2-3 years time, I'll get the successor to the D200, which should be almost up to my Olympus OM-2 standards of viewfinder...
 
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