Diffraction vs a good quality ND

minnnt

minnnt

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David
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Hi all. What are your thoughts on using a ND filter to shoot motorsports rather than using a lens at f11/f16/f22?

Would ideally like to be shooting at f5.6-f8 i think but still be able to achieve a good slow shutter speed.

Would a good quality 2-3 stop ND filter offer better final IQ than using a lens at diffraction limiting apertures?

If so, which do you suggest?

Thanks.
 
First of all I think the problem with diffraction affecting sharpness depends on the degree of magnification of the final image. A relatively small magnification may not show up the problem whereas a larger on may. To be honest I've not noticed any significant quality fall off shooting at f11-f13 on my Canon cameras . It's a question have you. If not the I would suggest it's not a problem. However If you have quality glass and feel the need to have a ND0.6 then buy a good one. I'd also suggest that if you use a UV or similar filter to protect the lens you substitute the ND for this, rather than have two filters on at the same time.
 
I presume you want the slower shutter speeds for panning along with the moving vehicle. If so I suspect that the diffraction softening of f11 will be a lot less than the inevitable loss in sharpness due to the inevitable slight deviations of your panning technique from theoretical perfection. You should be able to check the difference for yourself without using an ND filter by simply shooting on a dimmer day.
 
minnnt said:
Would a good quality 2-3 stop ND filter offer better final IQ than using a lens at diffraction limiting apertures?
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Putting the issue of diffraction to one side for a moment, you should consider the implications of 3 stops less light in the view finder and to the AF sensors. Of course they'll still function but the challenge will be greater.

Bob
 
Did you notice any degradation in image quality shooting at F16 ?If not , then it's not a problem. However you may want a wider aperture for depth of field reasons, in which case , if you can't lower the ISO enough it's got to be an ND filter.
 
I never got to shoot at f8 as the speed was too fast so i have no idea. The images are very nice though, but it just made me wonder if having the ability to shoot at a bigger aperture would improve the IQ any or if I'm just talking b*****ks (as usual) :D
 
minnnt said:
:D
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Well I'm a Rayban kinda guy but I know sporty types like Oakleys... :lol:

Seriously, I wouldn't know as I've never looked for one but I would imagine a man of your discerning taste would require a decent one - they do say don't skimp on filters...
 
I would say that provided you are happy with the results then all is fine. I don't think you'll see much difference between f8 and f16 unless you are going to take image quality to the extreme. However there is always that nagging doubt, could I have got a better quality image. There is only one way to find out and that is to splash out around £60 for a quality ND0.6 filter I know that doubt 'cos I've been there. In most cases it was well founded however here I wouldn't be so sure. If you decide to go ahead look at quality filters from Hoya or B+W.

My only concern would be the effect on the autofocus, if you use it. It's fine with no filter, but knocking back a fair bit of light may give a problem. OK the EVF may be fine but autofocus may be ( and it's only a maybe ) troublesome. There may not be enough light reaching the sensors for the mechanism to work correctly
 
Cheers. Had thought about a CPL so it could be worth a go. I've had a Hoya pro 10 stopper before and it was quite good.

I doubt the light would be an issue as it focuses fine in a dark room bit thanks for the heads up. The new firmware update for it is supposed to drastically improve low light AF anyway so that should cover that.
 
Af is effected by a 3 stopper. Even on a bright day. Not unusable but noticeable. That's with the 56 which isn't as fast as the 23 Ime.
 
minnnt said:
Cheers. Had thought about a CPL so it could be worth a go. I've had a Hoya pro 10 stopper before and it was quite good.

I doubt the light would be an issue as it focuses fine in a dark room bit thanks for the heads up. The new firmware update for it is supposed to drastically improve low light AF anyway so that should cover that.
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David, just be aware with a CP that as many race cars use lightweight alternatives to glass you can sometimes get some strange rainbow effects from windscreens etc.

Simon.
 
chris malcolm said:
I presume you want the slower shutter speeds for panning along with the moving vehicle. If so I suspect that the diffraction softening of f11 will be a lot less than the inevitable loss in sharpness due to the inevitable slight deviations of your panning technique from theoretical perfection. You should be able to check the difference for yourself without using an ND filter by simply shooting on a dimmer day.
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^^^ This.

minnnt said:
Thanks. Do you use anything Simon or am i just worrying about nothing??
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The latter. Diffraction is something to think about when shooting something like a landscape, on a tripod with mirror-lock-up etc, when ultimate detail is important. Though it's more of an issue with smaller formats like M4/3 that get hit much harder at higher f/numbers.
 
The loss through diffraction will be only a fraction of the losses through a slow shutter speed and added glass.
 
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