DOF - Why not?

[Bob G]

To be truthful I don't find the DOF Preview Button on my DSLR that helpful.
When the aperture stops down it is difficult to get any clarity or precision about what is in and what is out of focus.
I have some printed DOF tables but it is often inconvenient to drag them out when you are in the field. POSSIBLE SOLUTION
While searching google I came accros a DOF Calculator that one can download to your mobile phone http://www.jibble.org/dofcalc/ I was wondering if anyone has used DOF tables in their mobile phone or even if anyone has a better solution than that? POSSIBLE BETTER SOLUTION
The more I thought about it I wondered why the manufacturers like Nikon couldn't include these calculations onboard the DSLR. These days, the way the lense and camera communicate, they already have the information such as aperture/f stop, distance and focal length at the time you focus. So wouldn't it be a relatively simple matter to, say, when you press the DOF Preview button also get a readout of distance/focal length/near focus/far focus etc. This could be displayed either in the viewfinder or on the rear display screen.
Would others find this useful? or is this all second nature to the pros?
Please comment

Bob G

[losfp]

The only problem with that is that you would NEED to know the distances. When your subject is 15 metres away, it might not always be practical to measure the distance back to something in the background.

I don't use the DOF preview button often, but I find it easy to simply look for a second to confirm if something will be in focus.

[Bob G]

If I'm not mistaken then I think the camera knows the distance to what you have focused on. This is communicated back from the lens - not sure if its absolutely accurate.

Bob G

[Zeeke]

Wouldnt be hard, Nikon specialise in hunting optics including scopes and range fingers ... the problem is, with those kind of features fitted.. the camera would be super bulky since most range fingers judge distance by using 2 lenses and blending the image together... bit like our own 2 eyes and judges the distance... maybe if it fitted a laser range finger it'd be ok, but then you have the issues of pointing a laser in someones eyes lol...

Tim

[big pix]

Hi Bob .... your link is not working........... the best way to understand DOF is to get out and shoot........ the more you stop down the more that should be in focus........ but the more you stop down the slower the shooting speed........ or increase your ISO if the speed is too slow.......

The closer you are to your subject will show more or less DOF....... distance shots are harder to see DOF and this is where your experence will help....... so get out shooting

[Bob G]

Bernie

Thanks -I fixed the link.

I understand everything you are saying very well. - I just want more precision in certain situations paticularly with long focal lengths.

Bob G

[gstark]

Bob,

Have you looked at your lenses lately?

Many carry a DoF scale on their bodies, showing sets of near and far markers that, when focussed, will give you an idea of what the effective DoF range is going to be.

But this problem is one of the small and dim viewfinders that we find in many cameras today. If you're shooting in bright sunlight, then you won't notice the problem as much. I know I've used the DoF preview button on my film cameras heaps of times, and yes, it's not as easy on a D70.

But as Bernie suggests, there's no substitute for just getting out and shooting.

[dooda]

I tend to agree, the DOF button is pretty much useless in the digital age. It does work well though if someone starts asking you to take a picture of something. Just snap the DOF button and proclaim "got it!"

[Ordinary K]

Yep, I reckon Nikon could do this - they already measure distance-to-subject with their AF-D lenses and factor it into the metering (hence "3D Matrix" metering).

But personally I wouldn't use it.
Mostly because as Bernie said once you shoot enough pictures you get a feel for DOF.
But also because when I'm shooting I tend to wear an old black legionairre's cap. When I need to see fine/low contrast detail in the viewfinder I reverse the cap so's the flap covers my face and the camera. Even with the lens stopped down the brightest thing in my field of view is the viewfinder, and assessing DOF isn't too hard. (Doesn't work so well after dark, of course...)

... Just snap the DOF button and proclaim "got it!"

Now THERE's a good idea. Has anyone else had trouble with complete strangers coming up and insisting "No, no, no - you should take a photo of this!"? Hasn't happened to me often, but ^&%$!! it's unnerving when it does.

Keith

[digitor]

- I just want more precision in certain situations paticularly with long focal lengths.

Bob G

DOF calculators won't give you what you want. What you can do though, is to shoot lots of test shots with your lenses, and assess the shots with your criteria, printed to the sizes you want, and determine the DOF, according to your particular needs. With digital, this will cost you almost nothing, and will give you a much better insight into how to use DOF to suit your style.

(Basically, what big pix said!)

Cheers

[MattC]

I would not say that the DOF preview is useless on digital. The small, dim viewfinders do not help. A good eye cup helps enormously and is a far better solution than any hat - maybe not so good for those who wear glasses.

Cheers

[PiroStitch]

i think my dof button is broken...when i press it, i can't see anything it just goes black...and this is on f1.8 or 2.8...not f22