A while ago, when Hazy was doing a comparison of a couple of lenses, I said I'd find some time to do one to show the difference between a 600mm prime and a 300mm with 2x extender. Whilst this may seem to be somewhat over the top bearing in mind the sort of costs involved with some of these lenses, it does also provide an interesting view on what happens when you put an extender in front of a lump of glass. I found a willing subject in a local Puffin, prepared to stand still on top of an old water butt for a while and they are pretty heavy crops - helps to show up deficiencies. These are all done with the same settings on a 5D3 and processed identically to ensure equivalence.
Starting at f/5.6, this is the benchmark to reach - the 600mm f/4 Mk2. At f/5.6 the f/4 lens is obviously stopped down slightly, but the 300mm + 2x is max f/5.6, hence choosing that aperture
The 300mm f/2.8 Mk2 + 2x Mk3 is very much a lightweight and less costly (relatively!!) way to get that 600mm. Again at f/5.6 (ie wide open)
Definitely a bit softer to my eyes. However, all lenses are softer when wide open, so to see the effect stopped down, I bumped the ISO a bit, dropped the shutter speed and shot again, this time at f/9. This also allowed me to pull in another contender - the 300mm f/4 with 2x Mk3 extender. A far more affordable combo
So, once again, the benchmark 600mm f/4 Mk2
then the 300mm f/2.8 Mk2 + 2x Mk3
and finally, the 300mm f/4 + 2x Mk3
To my eyes, it looks like the results follow expectations - the 600mm is best, followed by the f/2.8 300mm. However, once again, I'm impressed with just how well the f/4 300mm lens performs here - this is a heavy crop don't forget. To show just how much has been cropped out, these are the 3 source f/9 images (and will also allow you to make an assessment of the background)
600mm f/4
300mm f/2.8 + 2x
300mm f/4 + 2x
If those last images look a bit weird, you may have to view them via the Flickr site (in Technical Tinkering). For some reason, high res images never seem to display properly for me when I view them on here!
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Find me on Flickr / All about your camera - The Getting off Auto Index
I will never understand this level but will bump it back up for those who can!!
Lot to learn
Thanks for taking the time to compare these prime lenses WJ, its really interesting to see how they perform and I too am amazed how good the 300mm f/4 + 2x was overall. The 600mm is exceptional with the detail/clarity it gives having no extender attached - it's a lens I will have to dream of owing as I would never be able to cope it with being so heavy and needing a tripod ..........as well as a mortgage lol All the images crop down very well without losing too much detail even with extender on the other two but I see what you mean with image 1 and 2 and 2 being softer losing that slight crispness.
A really worth while exercise so thanks for going to such efforts, really appreciate it. Going to bookmark this thread now !
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Regards, Hazel
This is a real masterpiece! I also wonder if it is worth using this http://fixthephoto.com/free-lightroom-presetsto get this effect?