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)
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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In reply to gaynorsl:
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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In reply to HAZY:
An interesting read Joe. The next question would be how are the usable focus points affected by the various options. It appears to me that the 300mm f2.8 with a 2x converter on performs marginally less well on that score than the 600.- with only the 1.4 converter it scores the same. The 300mm f4 with a 2x converter is presumably limited to centre point and centre point expanded. Obviously where the 300mm f 2.8 really comes into its own is making use of the dual cross hair points as well as its aperture. I do think the 600 f4 images are the cleanest and sharpest but I can see that many people would be happy enough with the 300 and 2x, considering how well it would perform on its own. I would think that the 300 f2.8 with the 1.4 converter is almost as sharp as without one. Food for thought _:).
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In reply to Bobs_Still_Retired:
Yes, you do lose all bar the centre points on the 5D3 with the 300mm f/4 + 2x as that ends up at f/8, although you get to use, erm, 20+ on the 80D (can't remember exactly without finding the book!). It's obviously slower to focus as well, but certainly usable should that pesky bird refuse to come closer.
The 300 f/2.8 bare is a wonderful beast, the viewfinder with these 2.8 lenses is so bright when you're used to smaller apertures. The 1.4x converter's effect on the sharpness is normally a struggle to notice - I'll try and get a few minutes to do some more comparisons later this week and add them in
In reply to Whistling Joe:
A gap of a few months, but I'm re-visiting this thread briefly as I was talking about this subject at the weekend with someone at Minsmere. It struck me I never added in the 100-400 with a 1.4x extender to give 600mm (well, ok, 560mm, but in the ballpark). So here we go, a few more pics as a reference, all at f/8 as the lowest f-stop all combinations can manage.
600 f/4 IS Mk2 at f/8 (wide open would be f/4, so this is closed down 2 stops)
300 f/2.8L IS Mk2 + 2x Mk3 at f/8 (wide open would be f/5.6, so this is closed down 1 stop)
100-400L IS Mk2 + 1.4x Mk3 at f/8 (wide open)
300 f/4 IS + 2x Mk3 at f/8 (wide open)
Once again I think the results (unsurprisingly) follow the money. It should also be noted that there was a bit of cloud around and I definitely think that detracts from the results you get with the 300 f/4 + 2x. If it comes out again this afternoon I'll try and fit in a couple of extra examples :-)
OK, sun's come out again, so moving my subject out of the shade, here are the three Canon ways to reach 600mm (relatively) affordably. All at f/8, which is wide open for the lenses once the extenders are added. The two 400mm lenses are obviously 560mm rather than 600mm, but I've cropped the images to be the same size
100-400 IS Mk2 + 1.4x
400mm f/5.6 + 1.4x at f/8
300mm IS f/4 + 2x at f/8
Deciding on a winner here is hard. The sunshine sharpens up the edges and shows you can get decent results with any of them. The 400 prime in this example edges the 100-400 maybe, though its lack of IS and poor minimum focus count against it as a general lens (I used these on a tripod). The 300 f/4 with 2x once again is a pleasant surprise, but the focusing is very slow compared to the other two, noticeably so, and would be hard to use for subjects moving around.
If anyone's nearby and has one of the Tamron or Sigma 150-600s, I really must try comparing the results of those as well :-)
Thanks again WJ for the great efforts you put in to comparing these lenses; all good results but got to say the 300mm f4 really exceeds what I would have expected; having said this, I'm not swapping my f2.8 lol !! I will peruse these again as they are mightily impressive .... but then again ..... your skills have an awful lot to do with it too ! Will be interesting if you can get your hands on the Tamron or Sigma for further comparison. Once again WJ, thanks, it is a really informative and interesting exercise and nobody should be put off opting for the 300mm f4 rather than the more expensive f2.8 If we have a week of good weather like this more often none of us would need f2.8 lol
Don't worry Hazy, every test I've done shows the 2.8 version is better than the f/4, but I'd be seriously worried if it wasn't! Using them all back to back does make you realise how quick that 2.8 lens is as well, even with extender attached. Ultimately I think that's what you're getting with the expensive hardware, the ability to get good images in less than favorable conditions. But learning the good & bad points of each lens can make a big difference to end results as you can work within any limitations
As you say, once you know the range of each lens, you can work with what they will allow; a lot of folk have asked me about the camera body, what is it I'm using and the ins and outs of the camera itself with its various bells and whistles but I mentioned it also matters and makes a more significant difference what you stick on the end of it lol !! I guess I should attach the 300mm on to the 7DmkII from time to time when I'm photographing wildlife but I'm so convinced the full frame 5Dmkiii is the better option for such a high quality lens as it still maintains brilliant detail even when I crop it to death !
It's funny when I altered the 5D to BBF like I did with the 7D and for the first couple of times I used it I had forgotten and started to panic when it wouldn't focus, I think I remember Paul A saying the same lol
I'm not a Canon user, but fascinating regardless.
If I had one thing to add, I'd say any camera/lens combo is only going to work to the limits of the weakest link. The camera model can make a difference, for example, cheaper models may not have the AF accuracy of their more expensive counterparts and putting a top-end lens on an entry level body isn't necessarily going to give the desired or expected improvement (unless you switch to MF). I guess that's obvious but it's not something I often see talked about (all tests tend to be done on pro-level cameras) and it may be worth bearing in mind for anyone thinking of an upgrade.
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