Comments on: Focus Charts and Retesting my Nikon 70-200 f/2.8 VR http://regex.info/blog/2006-11-08/276 Not a photo blog. A personal blog with photos. Mon, 21 May 2012 08:38:42 +0000 hourly 1 http://wordpress.org/?v=3.3.2 By: Arnaud http://regex.info/blog/2006-11-08/276#comment-3113 Arnaud Fri, 19 Jan 2007 16:03:48 +0000 http://regex.info/blog/2006-11-08/276#comment-3113 I'll use a tripod then, that should take care of any shaking problem :) Make sense to open wide to have the smallest depth-of-field, I mean shooting at f/32 would miss the point of the exercise. I’ll use a tripod then, that should take care of any shaking problem :)

Make sense to open wide to have the smallest depth-of-field, I mean shooting at f/32 would miss the point of the exercise.

]]> By: Jeffrey Friedl http://regex.info/blog/2006-11-08/276#comment-3112 Jeffrey Friedl Fri, 19 Jan 2007 16:00:57 +0000 http://regex.info/blog/2006-11-08/276#comment-3112 When I mention a fast shutter, it's to allow for a reasonably sharp image not marred by camera-shake induced blur. Such blur would not change the focus, but could hide the results. As a general rule, when trying to track down a problem in one area, you want to make other areas as problem-free as possible. With a 17-50, 1/500 will be more than enough unless you're drunk. Oh, and I forgot one other thing: shoot in aperture-priority mode, wide open. When I mention a fast shutter, it’s to allow for a reasonably sharp image not marred by camera-shake induced blur. Such blur would not change the focus, but could hide the results. As a general rule, when trying to track down a problem in one area, you want to make other areas as problem-free as possible.

With a 17-50, 1/500 will be more than enough unless you’re drunk.

Oh, and I forgot one other thing: shoot in aperture-priority mode, wide open.

]]> By: Arnaud http://regex.info/blog/2006-11-08/276#comment-3111 Arnaud Fri, 19 Jan 2007 15:54:43 +0000 http://regex.info/blog/2006-11-08/276#comment-3111 Thanks a lot for the advice. I will try that on my newly bought D80. When you say very fast shutter speed, are you thinking 1/500 or more ? I will use the chart with a 17-50mm lens. Thanks a lot for the advice. I will try that on my newly bought D80.

When you say very fast shutter speed, are you thinking 1/500 or more ? I will use the chart with a 17-50mm lens.

]]> By: Jeffrey Friedl http://regex.info/blog/2006-11-08/276#comment-3110 Jeffrey Friedl Fri, 19 Jan 2007 15:23:14 +0000 http://regex.info/blog/2006-11-08/276#comment-3110 Doh, yes, sorry, I forgot. <s>I'll try to prepare it properly over the weekend,</s> It's <a href='http://regex.info/blog/photo-tech/focus-chart/' rel="nofollow">here</a>. Best results when printed on high-quality matte photo paper (e.g. for Canon, MP-101). In short: ensure that autofocus can NOT lock on the gray parts (which is dependent on your printer, the paper, the lighting, and the camera), and ensure that there is PLENTY of gray area around the sensor when pointed at the focus line, to ensure that the autofocus can lock on the focus line and only the focus line. Realize that the sensor may actually be in a slightly different spot in the scene than the mark shown in the viewfinder (which is necessarily dependent on how your place your eye to the viewfinder, among other things). Use plenty of light, a low ISO, and a very fast shutter speed. The overall sharpness is not particularly relevant; you want to know where the focus line lies within the vertical range of what's more or less in focus. In all but extreme closeups, it's best if it's smack dab in the middle. [<b>UPDATE</b>: see the <a href='http://regex.info/blog/photo-tech/focus-chart/' rel="nofollow">Jeffrey's Autofocus Test Chart</a> page for verbose details on how to perform a test properly] Doh, yes, sorry, I forgot. I’ll try to prepare it properly over the weekend, It’s here. Best results when printed on high-quality matte photo paper (e.g. for Canon, MP-101).

In short: ensure that autofocus can NOT lock on the gray parts (which is dependent on your printer, the paper, the lighting, and the camera), and ensure that there is PLENTY of gray area around the sensor when pointed at the focus line, to ensure that the autofocus can lock on the focus line and only the focus line.

Realize that the sensor may actually be in a slightly different spot in the scene than the mark shown in the viewfinder (which is necessarily dependent on how your place your eye to the viewfinder, among other things).

Use plenty of light, a low ISO, and a very fast shutter speed. The overall sharpness is not particularly relevant; you want to know where the focus line lies within the vertical range of what’s more or less in focus. In all but extreme closeups, it’s best if it’s smack dab in the middle.

[UPDATE: see the Jeffrey's Autofocus Test Chart page for verbose details on how to perform a test properly]

]]> By: Arnaud http://regex.info/blog/2006-11-08/276#comment-3109 Arnaud Fri, 19 Jan 2007 13:52:52 +0000 http://regex.info/blog/2006-11-08/276#comment-3109 Any chance you will make the chart available ? Any chance you will make the chart available ?

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