Okay – I'll admit it – up until recently, I've borrowed the 300mm f2.8L IS lenses I've shot with. It is (tho not as much as I thought it was) a specialty lens that was just what I needed for some projects (like any professional cycling race) that I hadn't committed to buying… till now.
When the lens arrived (I'll spare you typical set of pictures of every square inch of the lens – you all know what one looks like) my first question (as for most folks) was "how good is my copy?". I managed to take a few shots around the office when I took delivery, but I had a busy day on tap, so I couldn't really play till I got home that evening. The moon was a day or two shy of being full, so I figured it would make a good test subject. In the shots I'd done at the office, I saw that I had no noticeable CA in my images at all… I decided to test with a 1.4x then 2x teleconverter handheld. I had great results (given that it was humid and fairly warm – lots of atmospheric "issues" making a great shot problematic). Again – zero CA so far, very fortunate for me…
The next day had a criterium on tap at a nice course in an area of Dallas that has some older homes that have been converted to office space. The course is the bane of most of the area cyclists because there are no long straights – nothing but two squares connected at a corner, lots of turns. This can be a challenge for a lens, but the 300 took it in stride… beautifully fast focus, with amazing bokeh.
So far – nothing was too out of the ordinary, but I was in for a surprise a few nights later. Some friends got together for a ride then dinner. As we left the restaurant I saw that the moon was just over the horizon and it was blood orange in color… Back at the house I grabbed my 1D3 and both my teleconverters. I walked out into the cul-de-sac in front of my house, I raised the lens, half pressed the shutter, and was surprised to hear the AF kick in. It did dance a bit, but it wasn't blind hunting. It worked steadily in and locked on…
I snapped a few shots and wondered if it would work on my 5D2 as well. Lo and behold – it worked again. I shot a few more photos with the setup on my tripod. I knew they wouldn't be tack sharp (too much smoke, humidity, etc), but was curious just the same. I gave it an hour or so and shot some more; with the now brighter subject, the lens didn't hunt around – it just focused. In reviewing the images, I was impressed that it a) had focused, and b) had come out with just minimal CA in the images with the stacked TCs. The CA wasn't evident in the orange photos (no color correction was done – this is how the moon looked – I think it was thanks to the wildfires in West Texas), but did show an hour or so later when the moon had climbed out of the smokey haze to shine brightly. Just a hint of cyan bleeding into the whites/grays.
The thing I should have checked (and will once I'm back in town and have my TCs at hand) was if my 70-200 2.8 will AF with the stacked set of TCs… With the 1D3 and the 5D2 – I was using the center AF point selected, had spot metering (to help it get correct exposure on the moon) with no other special (that I know of) fn configuration.
The EXIF data on the images only show the effects of the 2x TC… they show a 600mm exposure at f5.6 – essentially two stops off the f2.8 of the lens; but it should read 840mm at f8 (with the extra 1.4x and the additional stop lost from the second TC).
Next up for the 300 – doing the AF microadjustment with my camera bodies…
As always – use the comments sections below for any questions, or use the "contact" link above.
Thanks for reading!