This still entailed looking at countless images to see which had best focus. I did try processes that had very detailed targets which showed whether the camera/lens combination was focussing in front or behind where it should be. You just end up “goggle-eyed” and still have, what can be regarded as, subjective results. Each one entails capturing images at various settings. Multiply that by 3 bodies and you’ve got 39 tests to carry out. This entailed doing the manual check 0n 13 combinations per camera body. I also had to cater for a 1.4x and a 2x converter on some of them. In my instance I usually had three camera bodies and about 5 lenses, of which 4 were zooms. This can be a painstaking procedure, which years back I used to often give up on and leave the default setting of zero as is. There are a variety of methods to do this – generally manually checking the focus of a target image at various autofocusing micro-adjustment settings. The issue is how much adjustment you need and how do you measure this. Many even give you the option of making the adjustment at the shortest and longest ends of zoom lenses. This gives you the ability to move the plane of focus slightly forwards or backwards for that particular body/lens combination. Fortunately camera manufacturers have catered for this eventuality by having an “autofocus micro-adjusment” (AFMA) option in their menus.
However, due to the combination of small tolerances in each, the particular camera body and particular lens does not focus optimally at the focus plane. Individually there is nothing wrong with the camera body or the lens. The image is great, but not quite perfect! Need for AF Micro-adjustment You want the pupil of the eye of a subject (like a bird) to be in optimal sharp focus but on processing the image you find the feathers just in front of the eye or slightly behind the eye displaying the sharpest focus. The depth of focus of a 600mm f/4 lens for instance, particularly at shorter shooting distances, is minimal. You may have all of your lens techniques correct, but you seem to miss the vital focus point that you intended. At the best of times it is a challenge to obtain sharp focus particularly when using longer focal length lenses. This goes for all genres of photography but it is very true for wildlife photography. The one thing that makes or breaks a captured image – is absolutely sharp focus.
0 kommentar(er)
