DSLR Depth of field

[Kevvy]

Well tomorrow is the big day and I'm going out to take some landscape shots with my brand new camera.
It's been along time between cameras for me I used to use Kodachrome 64 and when I would set up for a shot I would use the hyperfocal gauge on the lens to focus and maximize depth of field.
Now with the new camera there is no gauge on the lens and the problem I have is how to do the focusing to obtain maximum depth of field. Do I let the camera handle the focus or shall I focus manually on the hyperfocal point, this could be a problem as my eye sight is poor and focusing through the viewfinder is a bit hit and miss.
I understand how to achieve depth of field I just need some tips on how to obtain it using a DSLR (Nikon D5100) any tips will be appreciated.
Cheers
Kevvy

[ricktas]

choose a smaller aperture (large number) and focus either 2/3rd of the way into the scene, or if the foreground is the primary interest 1/3rd of the way in.

Now depending if you are going for dawn, you might find you need to manually focus as autofocus may have trouble. Most AF systems work on contrast to lock focus, thus you cal lock focus on the edge of a cloud, but not on a plain blue sky. So you might need to use manual focus if AF doesn't work.

A DSLR is a film camera with a sensor instead of film..everything else works the same.

[ameerat42]

(A sad shortcoming of modern lenses, though in keeping with the modern trend of profiteering - itself an outgrowth of normal profit-making.)
(If you are worried, profit is a gain commensurate with effort/skill required, while profiteering is just the usual rip-off.)

Now, "hyperfocal distance tables" in Google will result in a heap of references, one of the better-looking early ones being from here (http://www.cambridgeincolour.com/tutorials/hyperfocal-distance.htm), The Cambridge Encyclo....

A(Hmm! Might use it myself.)m.

[Lance B]

A useful DOF guide here:
http://www.dofmaster.com/dofjs.html

DOF markings are generally to be found on prime lenses (all my current Nikon Primes have them and so did all of my Pentax primes when I used Pentax), but rarely on zoom lenses.

[Mark L]

Well tomorrow is now today!
One point though,

...., this could be a problem as my eye sight is poor and focusing through the viewfinder is a bit hit and miss.



Just in case you don't already know, adjusting the dioptric knob may help. Not sure where Nikon have it, Canon's little dial is top right of viewfinder.
Imagine Nikon would also be close to the viewfinder.

[cupic]

Bryan Peterson suggest f/22 focus @ 1m everything in focus from 14" to infinity

cheers

[ricktas]

Bryan Peterson suggest f/22 focus @ 1m everything in focus from 14" to infinity

cheers

I rarely use f22. A lens is never its sharpest at either end of its aperture range. I usually shoot around f14 - f18

[JM Tran]

Bryan Peterson suggest f/22 focus @ 1m everything in focus from 14" to infinity

cheers

I'd have to disagree with Mr Peterson as stopping down on a DSLR at f22 is at the far scale of 'diminishing returns' regarding severe diffractions in the sharpness of a lens.

You wouldnt notice much difference in a deeper depth of field at f14/16 compared to f22, but you can see a difference in lens sharpness falling off.

[mongo]

I'd have to disagree with Mr Peterson as stopping down on a DSLR at f22 is at the far scale of 'diminishing returns' regarding severe diffractions in the sharpness of a lens.

You wouldnt notice much difference in a deeper depth of field at f14/16 compared to f22, but you can see a difference in lens sharpness falling off.

Mongo was going to say exactly the same thing and totally agrees. Taking a lens to its extreme f stop limit is really pushing it and will generally not yield its best results - certainly, you may lose more than you hope to gain by doing that.

Even when using Mongo's 20mm he uses hyperfocal distance and never stops down more that f11 to get the best results.

[Lance B]

Depending on the camera, and this is due to the Mp count and physical size of the sensor, diffraction starts to set in the smaller the aperture is - or the larger the f number. Good explanation of diffraction here:

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

Lower Mp FF cameras, like say the D700, this diffraction sets in at about f11-f16, higher Mp FF camera, like the D800/E, this sets in at a lower aperture like f5.6-f8. The decision to work out is whether the diffraction makes the result worse than a slightly less DOF. This also depends on the lens being used and the subject matter and what you're trying to achieve. If you are shooting an average landscape with a FF camera with reasonable distance to foreground subject matter with a very wide angles lens, like say 20-24mm or even less (14-16mm on APS C), then f22 isn't going to make a lick of difference to the overall DOF when compared to say f16, or even probably f11, as there is an inherent large DOF for 20-24mm lenses. However, if you were shooting the same scene with some very close foreground subject matter, ie trying to emphasise some foreground detail, then you may see a small advantage in DOF in using a smaller aperture like f22, but at the expense of overall sharpness. If you use an extreme wide angle lens, like 16mm on a FF camera (10mm on APS C) then it is even less of an advantage to be too concerned with using a smaller aperture like f22, due to the fact that distant subject matter is so small that it is almost impossible to dilineate that subject matter anyway.

When using a higher Mp cameras, like the Nikon FF D800/E or 24Mp Nikon D7100 APS C cameras, diffraction sets in at lower apertures like f8. However, using a similar aperture, like f16, on these higher Mp cameras as you did on a lower Mp camera like the D700 won't have less overall sharpness on the D800 than on the D700, just that you may not see the advantage of the higher Mp's extra resolution. In otherwords, it won't look worse on the D800, just that it might not look better either. This is the trade off of higher Mp's. It's not that diffraction sets in specifically due to the higher Mp count of these high res cameras, but merely because the extra resolution offered allows you to actually see it when you wouldn't have been able to see it on the lower Mp camera's. It's still there, so to speak, just that due to the lower res it can't resolve it well enough for you to be able to see it.

This applies to macro shots as well, where DOF is usually very limited due to the fact that DOF reduces as your camera to subject distances is reduced and the fact that you are using a longer lens, like a 100mm macro.

[arthurking83]

....... Do I let the camera handle the focus or shall I focus manually on the hyperfocal point, this could be a problem as my eye sight is poor and focusing through the viewfinder is a bit hit and miss.
I understand how to achieve depth of field I just need some tips on how to obtain it using a DSLR (Nikon D5100) any tips will be appreciated.
Cheers
Kevvy


My preferred method is to focus in Liveview mode at the point that is most likely to give me:

a/ the DOF I want,
and
b/ the sharpest rendering at the most interesting point in the image.


using pertures ranging from f/4 all the way to f/29(in some rare instances).

While it's true that diffraction will take effect at apertures ranging in the f/16 and smaller range, the actual effect on the ENTIRE image is questionable!
The increase in DOF and with careful and considerate use of sharpening all basically cancel each process out in the long run.

If the sharp rendering of the microfine hairs of a caterpillar, on leaf, on a tree..... 50m away and using a 18mm lens is the kind of pixel peeping that is required, then f/22 is not going to suit your purposes.

if displaying good quality images on the whole, with little or no cropping is important ... you won't see any difference in pixel rendering on the ENTIRE image no matter if you choose f/5.6(sharpest) or f/29(smallest) aperture value.


Diffraction is an important consideration if the detail is small and important enough to become severely affected by it.


You will see more of a loss of pixel detail from mirror slap, breezy conditions, not so sturdy support system ... etc.


Anyhow, hopefully it all worked out for 'ya.

[Kevvy]

Thanks for all the replies guys learnt a lot. I found it interesting about diffraction at higher apertures and will do some tests.
Yesterday's outing went well some of the shots look ok in camera now I have to process and edit. Another steep learning curve, may post some results in this thread In a while.
Cheers
Kevvy