FX sensor limitations?

[gaule]

<p>I use a Nikon D700, mainly for landscape photography, and usually try to include some foreground interest with as much DoF as possible. For this I tend to use hyperfocal distance and Single Point AF, but here a problem arises. The desired focusing point will normally be a short distance in front of me, in the lower third of the image, yet even the lowest AF sensor that I can choose on this FX camera is still too high. (Using a DX camera like the D300, there is less of a problem because the 51-point array covers a larger area of the total sensor surface.) You might say, just focus on what you want and reframe, but I have found that the resulting down and up tilt in the focal plane, however small, is usually sufficient to produce a perceptible loss of sharpness. Even when I stop down as much as possible to create greater DoF, this cannot be avoided completely. I use a 14-24mm f 2.8 and 24-70mm f 2.8, and know through experience that both are capable of excellent sharpness. Have others found this difficulty and found as well a way around it?</p>

[walterh]

<p>PJ I must miss some point in your post but why do you not focus manually?</p>

<p>The AF points are where they are and cannot be moved so if you do not want to reframe I see no way to solve your problem by AF using AF points - it is logically impossible.</p>

<p>The typical way (at least for me) would be to use life view and to zoom into the region of interest for manual focus. Yes it would work best from a tripod but even hand-held you would avoid any focus shift from recomposing.</p>

<p>You get several benefits at the same time. First you can focus exactly independent of viewfinder and AF shortcomings and secondly you get an exact view of just how good the hyperfocal distance setting will render your landscape - for large prints you may have to close down one or two stops beyond rule of thumb settings for hyperfocal apertures.</p>

[CvhKaar]

<p>Hi PJ.<br />I do not know about the D700, because I do not own it.<br />On totally manual with my old rollei SL66, if i want a "close by focus "for landscape-ing, i use an object ( for example walking stick with an point, which I stick in the ground, but any object which is tall enough) which i put in front of the camera at the closest point I want to focus on, then manually focus ( no choice with the rollei...) , take the object out of the picture , and then shoot..<br />I know this all sounds a bit "clumsy" but it works a treat for me.......</p>

[ShunCheung]

<p>Manual focusing, especially in conjunction with live view, solves the problem for landscape photography.</p>

<p>In live view tripod mode, you can also AF from any point within the frame.</p>

[bjørn rørslett]

<p>AF and landscapes - you're joking, yes???</p>

<p>Liveview (tripod mode) if you can't do it manually directly in the viewfinder.</p>

[oskar_ojala]

<p>Put the camera on a tripod and use live view to focus. If you prefer focusing using the viewfinder, get a better focusing screen for the D700.</p>

[hans_janssen]

<p>When I use the hyperfocaldistance I don't focus through the viewfinder at all, set the HF distance, with the calculated DoF, and click, click, click...</p>

[mark_mandell]

<p>Helps to know your lens. As you stop down to increase the DoF, you're opening yourself the aberrations in the glass that may mess with your focus. Check the charts for your lenses and let them be part of your guide for HF. AF is great for fast p&s work, but for landscapes I tend to flip my D700's switch up to "M" and go to "A" on the command dial. Running in full "P" mode shows me how well the Nikon engineers could walk and chew gum while patting their heads and rubbing their bellies, but I get better pictures if I don't abdicate all my prerogatives to the camera.</p>

[dpbours]

<p>@Oskar<br>

The focussing screens cannot be replaced in the D700.That was possible in the good old film days.</p>

<p>But yes, manual focus would be my pick as well...</p>

[bill_pearce1]

<p>If you are trying to use the principal of hyperfocal distance, then the AF needs to be turned off. Once the hf distance is set on the lens, then you shouldn't change things.<br>

I' assuming ( Yes, I know what my fifth grade teacher said about that.) that ayou are using lenses with good dof scales. Note that these may be a bit optimistic for digital.</p>

<p>Bill Pearce</p>

[gaule]

<p>Many thanks to all for the helpful replies. Yes, I think manual focus is the way to go.</p>

[douglas lee]

<blockquote>

<p>As you stop down to increase the DoF, you're opening yourself the aberrations in the glass that may mess with your focus.</p>

</blockquote>

<p>Cameras generally focus at the largest aperture and don't stop down until the shutter is released. No?</p>

[bjørn rørslett]

<p>The post was a little unclear, but focus shift occurring when a lens is stopped down is a reality. That's why LiveView (done at the actual shooting aperture) is such a valuable tool for getting pin-point focus. Obviously, this only works for slow-moving subjects, but landscapes tend to belong in this category.</p>

[mark liddell]

I have no idea why you would want to use AF when shoot landscape with large dof.

 

Even with 35mm there is often a problem with getting enough dof, especially if you don't want to use the samller apertures due to diffraction. I use helicon focus and focus blend.

[mark_mandell]

<p>Douglass, with the camera on <em>manual</em> focus and the exposure set for aperture control, the camera is only picking the shutter speed, based on ISO and aperture set. While smallest apertures give greatest DoF, they also exhibit greatest diffraction which can degrade contrast and focus. Thus, for a given lens, you may get better IQ across more of the image at f/8 than at f/22. It's the aperture at which the picture is actually captured that controls the focus "quality" of the image.<br>

I notice a difference between engineers and photographers when I look at new lenses that don't have DoF scales (or minimal ones) etched at the distance window. It's like somebody decided that they aren't needed anymore.</p>

[lesterphoto]

<p>If you are shooting a subject that doesn't move, then go to Live View to focus. To further check focus, press the '+' button on the back of the camera to zoom into the image. Adjust focus and press the shutter when you're ready to make an exposure. It's that easy.</p>

[oskar_ojala]

<p>@Dennis<br>

I've replaced the screen in my D300. A friend of mine replaced it in his D3 or D700, I don't remember which. It is possible, one just needs to get a replacement screen. A Canon screen can be cut to suit a Nikon.<br>

I don't think hyperfocal distance focusing has much in landscape photography these days; we have excellent tools, such as live view, which are far more accurate in getting the desired focus. There is no need to guess the focus with a high-end DSLR when the subject is stationary.</p>

[mark_mandell]

<p>Kqatz-eye makes a split-image focusing screen for the D700<br>

http://www.katzeyeoptics.com/cat--Nikon-DSLRs--cat_nikon.html<br>

But I'm told that changing them out takes real care to prevent damage. Personally, I prefer Live View.</p>

[scott_murphy_photography]

<p> I apologize in advance for my tone but this is a real pet peeve of mine.<br>

Turn off the damn autofocus and focus <strong><em>manually</em></strong>. Cameras are <strong><em>dumb as rocks</em></strong>, they do no know what you want to do. To me it sounds rather futile, and kind of dumb (nothing personal) to want to work in hyperfocal distance, while still <em>letting the camera do the focusing</em>. <em>Take back control of the photographic process</em> <em>and stop letting a <strong>machine</strong> do the thinking for you</em>. <br>

Mark mentions a split image focusing screen for the D700. I found a better one that is a microprism surrounded by a ground glass collar and a fresnel screen. It is what I use with my D700 (and all manual AIS lenses) and it works perfectly. You can find it at focusingscreen.com at <a href="http://www.focusingscreen.com/index.php?cPath=22_92">http://www.focusingscreen.com/index.php?cPath=22_92</a></p>

<p>It is also about $30 cheaper than the Katz Eye.</p>

[mark_mandell]

<p>Bingo!! Thank you Scott. That is the screen that I've been looking for! I used a similar screen, basically focusing on the fresnel on my OM-1. It never let me down.</p>

[scott_murphy_photography]

<blockquote>

<p><a href="http://www.photo.net/photodb/user?user_id=5477009">Mark Mandell</a> <a href="http://www.photo.net/member-status-icons"></a>, Feb 19, 2010; 06:25 p.m.</p>

 

</blockquote>

<p>It works like a champ Mark. And I have no problems with it blacking out even with my 300mm f/4.5 Nikkor and TC-14B. Of course. The microprism is no longer useable with my 500mm f/8 Reflex Nikkor, but the groundglass is fine enough and the depth of field so shallow with that lens, that it is still perfect and I have no problems focusing. The one thing I did find out with this screen, however, is that the focus confirmation of the D700 is not always correct. </p>