D4/800 AF/LV Focus Check- Use LR
9 months ago
Not sure if this procedure has been discussed in an earlier thread. Searched but could not find it, but if it has been, my apologies.
In any event, if you are comparing D4 or D800 AF points, or comparing AF with LV focus, LR4 (or earlier versions) offers the perfect tool- side by side image comparisons at 1:1 (or whatever size you select) in real time. This allows you to directly compare 2 images across the entire photo, since the comparison image is synced to the reference image. So, you can view the reference at 1:1, and the comparison image will display exactly the same image area. You can then scroll up, down, or across and the comparison image view will follow exactly. Thus, you can compare identical image areas directly using different focus points, or compare AF to LV.
The procedure to do this is as follows:
1, Obtain the comparison images according to a standardized testing method, such as that suggested by Thom Hogan.
2. DL the images in ViewNX 2 and turn the focus indicator control on.
3. RELABEL your images according to the focus area (e.g., L, R, or C) and focus method (e.g., AF, LV, MF). This is an important step becasue LR will not display the focus points and if you do not label the images here you may confuse them.
4. Import into LR in Library mode.
5. Select your reference image (e.g., LV Left focus point); then select a second comparison image using the Cntrl key on PCs (e.g., AF Left focus point).
6. At the bottom of the window, select the dual view (2 images) pane.
7. In the reference photo, magnify to 1:1 (or whatever setting you prefer). The comparison image will increase to the same size, and the view area will be the same as that in the reference image.
8. Use your mouse to scroll across or up/down in the reference image. The comparison image is synced and will follow your scrolling.
Using this procedure I compared AF and LV focus points in both my D4 and D800. What I found using this comparison method was very clear: Both the L and R focus points on my D800 were off when compared to the LV images at the same focus points. The LV areas were in almost perfect focus, while both the L and R areas were not. In fact, in my D800, the R seemed to be worse than the L when AF was used. The center focus point images were almost identical and clearly in focus.
On my D4, comparisons of focus points between LV and AF were almost identical. I had no R or L AF issues with that body. In fact, if anything, the AF images appeared slightly sharper at 1:1 than the LV images, but all were very sharp.
Up to this point I was unsure how much of a problem I had with my D800 since I had to compare images by shifting back and forth. Using LR, the differences are very obvious. Also helped my faith in my D4 since this confirmed that I have no focus problems in that body.
Based on this, I will be sending my D800 in for adjustment once it becomes clear that Nikon Melville is routinely repairintg these cameras the first time.
Michael E. Clark
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