IQ Check

[KeithS]

This was taken from the ground (my yard) with the 5D3, 100-400 Canon lens and the Canon 1.4 II extender (540mm).  Settings were 1/1250 f/8 ISO 100.  I brought up the exposure 1.79 in LR and a little noise reduction.  Cropped a good bit. Should I expect to get better IQ than this?

[FelipeG]

For some reason I was under the impression that the 100-400L/1.4x combo was only supported with 1D bodies, and that when using non-supported bodies the exposure tends to be a bit off.

My only experience with the 100-400L/1.4x is that at 540mm it does get soft (1.4x II is what I have), the image was not the best, but not something I could complain about. This was on a 1D Mk III and in the middle of the Ohio winter, so there's minimal heat distortion.

To me it looks like you really cropped the image, or that the exposure was way off.

[Scott Youmans]

Keith, Based on the EXIF data it looks like it was about 2.5 stops underexposed.  The large amount of bright sky (or what should have been bright anyway!) might have had something to do with that.  For the conditions the settings should have been equivalent to about 1/400 sec at f/8 (ISO100).  The underexposure at least partially explains the noise.

[KeithS]

Felipe and Scott, thanks for the thoughts.

The 5D3 with the latest firmware will auto focus at f/8, though more slowly, and it appears not spot on.  Yes, the image was cropped to about a third of the original dimensions.  I realize that is best to try to fill the frame, but in this case the plane was at least 1500 feet away (overhead).

I went back to the photo in Lightroom and raised the exposure to plus 2.5 stops.  That's definitely about where it should have been in camera.  This was my first attempt at adding the extender to this lens to follow something in flight.  I used a custom setting which does reasonably well for birds in flight, thought it is not so good for aircraft (with the extender).