200600mm +1.4x TC @ infinity focus - Sharpness issues.

Started Jun 25, 2021 | Discussions thread
FrenchKiss78 Regular Member • Posts: 377
Re: 200600mm +1.4x TC @ infinity focus - Sharpness issues.

JerseySailor wrote:

jbuzzinco wrote:

FrenchKiss78 wrote:

If you are using a filter, take it out. This lens AF simply cant work properly with one.

Heat haze lurs the AF on the distance, especialy close to the ground.

The FE 200-600mm works with filters. Using a good quality filter is important if you don't want to degrade image quality. But saying that the lens doesn't work properly with filters is baseless.

All of this talk about filter crapping out the 200-600mm lens drove me to shoot some test shots today, with and without the UV filter, with both autofocus and manual focus. The setup is shown here:

Setup shot with 55mm lens, showing target window 575' away

The camera was tripod mounted, Steady Shot off, remote shutter release to minimize vibration, five pound weight hanging on tripod to add stability. All shots at 1/1000 sec, F9.5, ISO 1600, 200-600mm G lens with Sony 1.4TC. Kitchen window was open to avoid shooting through the window. No post processing other than cropping.

Test photos were shot with both manual focus and auto focus, both with no UV filter, and with a $155 B&W F-Pro UV Haze 1X MRC. As you can see, there was little difference in detail between shots with or without the filter. Of course this was a high end, expensive filter. If you use a cheap junky filter, expect junky photos. In all four photos, you could even tell if the window lock was open or closed - from a 10th of a mile away!

Here are the results:

100% Crop - No Filter - Auto Focus.jpg

100% Crop - No Filter - Manual Focus.jpg

100% Crop - With Filter - Auto Focus.jpg

100% Crop - With Filter - Manual Focus.jpg

Great test but the point is using filters for fast action or bif. That is where the filter is messing with the AF.

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