how to photograph a black dog at night

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<p>Pete, I hate to tell you ... you sort of refuted yourself in your first couple sentences. If your scene is 0EV your meter might work, but you probably won't have enough contrast for the AF points to lock into something. If you're using an f/2.8 lens on a cross-type AF point you might be okay, but you're pretty much out of luck otherwise.</p>

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<p>Zack, I'm not sure exactly what you are referring to.<br /> The OP was using a f/2.8 lens and if he would have switched to single point af and select the center one on the D90 he would have been using a cross type AF point. But I agree that anything slower than would have been problematic in any kind of low light.</p>

<p>I mentioned the metering just because I assumed the OP didn't have a light meter or could estimate light levels. The meter starts flashing if it's below 0EV. Nikon says the AF will work down to -1EV though. Exactly how much contrast or subject reflectivity is required for that I don't know. But I know from experience that you can get the AF to lock on a black subject even when the metering is flashing. But it requires a little more than point and shoot. As I mentioned above I prefer to "scan" the scene with af-on and af-c (in release priority). When I see that the AF finds something I stop focusing, compose the scene and shoot.</p>

<p>For those not familiar with EV, if you would shoot a scene at 0 EV, handheld with a f/1.4 lens using ambient light only you would get an exposure like f/1.4, ISO6400, 1/30s. My guess is that the light levels the OP experienced was a little higher than that.</p>

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<p>(1) focus on something same distance away that has a well defined edge such as the windshield frame, then press the focus lock button and hold, then recompose, then take shot.<br>

(2) flip the switch to manual and manually focus the lens.</p>

<p>The flash hitting the windshield directly like that didn't just make a big flash ball?</p>

<p>Kent in SD</p>

<p>Were you by any chance taking the pic from the front through the windshield? That piece of glued safety glass might have disabled all AF sensor stuff due to its polarizing action on light. Just a thought. </p>

<p>So, please try this again without dog and practice until you figure out how to do this with your gear.</p>

<p>Try dynamic autofocus mode. The camrea will find an autofocus point for you, hopefully somewhere within the DOF you need. I use it for self portraits and its reletively fast as long as there is SOMETHING the AF system can lock onto.</p>

<p>In the immortal words of Khan in Star Trek 2: "<em>The override</em>. Where's the override?" <br /> When it all falls apart and I can't lock into anything, I'll switch to manual and get the job done. Maybe try to find a sharp edge in the same plane of focus as my item of interest. And then, when I get home, I learn how to deal with that so the next time it happens, I'm ready.</p>

<p>And as a last resort... "Paint it white !!!" :-)</p>

<p>Sorry, couldn't help myself ... :-)</p>

<p>Pete: What I meant was that under the situations he described he might be able to get AF to lock in on the centre point(emphasis on 'might'), but that if he was using another point he was pretty much boned. Or - and this was meant for the rest of the readers that may not have a 24-70 f/2.8 - that if you tried doing the same thing with a darker lens, you would also be boned.</p>

<p>As far as f/1.4 lenses go ... someone may be able to correct me here, but I believe that there is a limit to the amount of information an AF sensor can use. I seem to recall reading that a cross-type sensor gets all the information it can get at f/2.8, while a non-cross sensor is around two stops darker; it would function as well at 2.8 as a cross-type would with a 5.6 lens. If this is true, that means that using an f/1.4 lens would make your AF points catch focus better, but you'd still be limited to the same level of performance as a cross-type at 2.8.</p>

<p>The reason I mentioned the meter is relation to AF is that light is required for AF operation. If the dog had on a shiny (or bright) collar, awesome. But if not, the camera is literally guessing. And if may guess correctly, but it's guessing. During the day, a black dog on a black background will still have some shading and depth; at night, it has neither. It's true that the D90s uses phase detection and not contrast detection, but without some amount of shading and depth the camera will have difficulty making out edges, and may not know where the dog ends and the car seat begins. Phase detection still works in extremely low light - unlike contrast detection - but it works poorly.</p>

<p>Again, this doesn't mean that the camera isn't able get focus properly. It DOES mean that it will likely require several attempts, and the dog will probably get bored and go away long before the camera does it correctly. So even though I agree that the possibility is there to do it, it's basically not going to happen unless you're very lucky.</p>

<p>Thanks for clarifying Zack and I agree with you 100% on focus points and f/2.8 lenses.</p>

<p>However when you shoot black on black it is not the shadows that creates depth because a shadow on something black will just be...black. What creates depth and form on black is specular reflection, shine if you like. And black dogs are shiny (at least healthy ones) and black cars are very shiny. So they will reflect any light that hits them. And that's what you can focus on (literally).</p>

<p>If there is NO light well then you can't focus but then you wouldn't know the dog was in the car either. And you wouldn't be able to walk there because you can't see where you were going :-)</p>

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