Photo Focus tag:www.mapability.com,2007-10-23:/blogs/photo//4 2008-03-14T14:18:38Z Commenting on Hardware, Software, Technique, & Sales. Movable Type Publishing Platform 4.01 Focus Problems with Nikon D300 body and 18-200mm lens tag:www.mapability.com,2008:/blogs/photo//4.84 2008-03-14T14:16:14Z 2008-03-14T14:18:38Z I am now the proud owner of a Nikon D300 camera, and a couple of Nikkor lenses. During my 20+ years of taking travel photos I have moved from Olympus OM1 to OM2 to OM4 (and accompanying Zuiko lenses), and... Tim Makins I am now the proud owner of a Nikon D300 camera, and a couple of Nikkor lenses. During my 20+ years of taking travel photos I have moved from Olympus OM1 to OM2 to OM4 (and accompanying Zuiko lenses), and then more recently to digital. I bought a small Sony DSC-P43 when a need arose to produce photos to illustrate adverts when down-sizing my possessions on eBay. This little camera subsequently travelled to Africa on my last Overland journey, and excelled itself in a range of difficult environments, providing me with some outstanding, albeit low-resolution images - you can see them on my 'Travelling Tim' blog pages. I realised that if I wanted to continue to produce the quality of digital photographs that I had previously captured on film with the Olympus cameras, I would need to quickly move up-market. After much research, I decided on the latest in the Nikon semi-pro range, the 'D300'. To accompany it, I chose the Nikon AF-S Nikkor 18-200mm 1:3.5-5.6 G DX SWM VR ED IF, and the Nikon AF-S Nikkor 12-24mm 1:4 G DX SWM ED IF.

Whilst experimenting with my new camera, and taking a variety of test shots, I soon noticed that when I zoomed into images taken with the Nikon AF-S Nikkor 18-200mm lens, they were never as well-focused as I expected. After some searching on the internet, I quickly realised that I wasn't alone in this, and found comments such as "Not to worry...this is a common problem with the 18-200mm lens", which was both comforting - I was not the only one, and yes it can be fixed; and annoying - that I had to waste time with this at all, and why couldn't Nikon have adjusted things properly before they left the factory!

I checked the D300 Manual. Nothing in the index, nothing in the Focus section. It was only because I'd read about it on the Internet that I persisted, eventually tracking down a small section entitled 'AF Fine Tune' on page 327. Ironically, the picture on that page shows adjustments being made for an 18-200mm lens! A suitable chart for setting up the focus, and a suitable method of performing the adjustment was needed. From the posting mentioned above, 2 resources were found:

Jeffrey’s Autofocus Test Chart

Nikon D70 Focus test chart

I tried taking a range of test shots using these focus charts, but found it rather difficult to determine the best results within a small range. I then took a series of photos outdoors, using different 'AF Fine Tune' settings for each.

Lightroom is a good program to open the RAW files with, but it is hopeless when comparing each shot, due to the amount of time it takes when loading each file. What was needed was to be able to view a small, highly zoomed section of each image, and to compare these sections simultaneously.

In the end, my favourite method was to zoom in with Lightroom at the 3:1 setting, then screen-grab a small section of the image and convert to .png. I would then open all these small photos together on the screen, and found it much easier to see which was the best, and consequently which setting I should use for each lens. As it turned out, I needed -6 for my 18-200mm lens, and -2 for my 12-24mm lens. Don't use these figures yourself, though. You will need to take a series of test shots to decide what your own settings should be.

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