Canon EF 300mm f/4.0 L IS USM Lens

[Julius]

It's a terminal disease called "gearlitis"..but what the hell, you seem to be doing ok

[wickerprints]

It's a terminal disease called "gearlitis"..but what the hell, you seem to be doing ok
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AKA "Gear Acquisition Syndrome" (GAS)... and if you ask my wallet, it would most definitely be telling you that I am NOT doing okay. [:P]


I just heard about a price drop on the EF 300/2.8L IS. I could get one for just under $4000... the reptilian part of my brain is literally screaming "I do not want to lose out on this deal!!!!"

[wickerprints]

My 300/4L IS arrived yesterday. It's just about perfect right out of the box. No need for microadjustment.


But seeing as how this is the longest focal length lens I have used so far, during testing of this lens I discovered some interesting behavior.


As I was checking for focus accuracy, I had the 5D2 + 300/4L IS mounted on a tripod and took some shots with IS off. I saw vertical blurring and quickly concluded that mirror bounce was causing the problem. FWIW I did not observe this with the 70-200/2.8L IS mounted on the same tripod with IS off.


Next, I repeated the exposure with IS on. No change whatsoever in exposure, which makes me wonder if this lens' IS system is tripod-sensing, because with the 70-200/2.8L IS, if I turn on IS while on tripod, I get much blurrier images in all directions. This is confusing since the 300/4L IS was designed before the 70-200/2.8L IS.


Anyway, to confirm the issue with mirror bounce, I enabled MLU and repeated the two exposures, one with IS on, one with IS off. (All four exposures were taken on 10s timer @ 1/30-60s shutter speed.) In this MLU test, I saw a sharp image in each case--IS mode again made no difference.


Because the influence of IS was not yet observed, I unmounted the camera from the tripod and repeated the experiment handheld, MLU disabled and enabled. Again, exposure was about 1/50s, so more than 2 stops slower than 1/300s. With IS on, I was able to get a very sharp exposure, no directional blurring, both with and without MLU. So the IS system does work.


Based on this result, I conclude that 5D2 + 300/4L IS + tripod = MLU at intermediate shutter speeds (1s - 1/300s). The reflex mirror on the 5D2 induces a great deal of shake. Perhaps the tripod I am using is too light to damp the vibration, but these were my findings. My next step will be to try IS mode 2, to see if the panning mode will permit the IS system to recognize the vibration from the mirror.


Comments, questions, thoughts welcome []

[Colin]

Great bird shots.


I don't have that lens!


I'm not buying more lenses, I'm not buying more lenses, I'M NOT BUYING MORE LENSES!