Hello all, with these two lens and teleconverter combo's giving approximately the same focal length and maximum aperture of f8.0, would the 400 & 1.4x combo be sharper because of the 1.4x teleconverter factor. I'm talking with a EOS 3 body so they will auto focus and Canon teleconverters. Look forward to your thoughts. Jason.

-- Jason Eadie (jason_eadie@hotmail.com), October 20, 2001

Answers

My guess would be that the 400+1.4X would be sharper, but at that kind of length, neither will be brilliant. However, the 300 does work very well with the converters (I've heard that they were initially designed with the 300mm F2.8 in mind, so work best for 300mm lenses (this may be utter rubbish however)), esp the 1.4X tc. I will be getting a 2X tc for my 300mm F4L IS once I get an EOS 3...

-- Isaac Sibson (isibson@hotmail.com), October 20, 2001.

According to the MTF tests at photodo.com the 400f5.6 is sharper to start. Also supposidly the 1.4 is very good with little loss in sharpness while th 2x has quite a bit more loss. I doubt the IS will make up for the lack of sharpness to start with. I'd be interested to see your results.

-- Rob Olling (robertolling@msn.com), October 21, 2001.

"According to the MTF tests at photodo.com the 400f5.6 is sharper to start."

Not true. Photodo gave the EF 400 5.6L USM zip because it is an untested lens. However, the F2.8 IS version is rated at 4.4. The EF 300 4L USM is rated at 4.3 while the newer IS version is a farty 3.4.

I have the EF 300 4L USM and it is as sharp and contrasty as a whip. The EF 300 4L USM is nearly flare-free and can take eye-frying Hawaiian sunsets without a hitch (don't try this with a zoom). With the EF 1.4x Extender this combo is nearly as good, i.e., it is excellent

I don't have the EF 2x so I can't comment on quality, but a F8 aperture is very undesirable. Pop Photo tested the EF 400 5.6L USM a few years ago and gave it a mediocre rating (and they tend to be generous).

Aloha

-- Puppy Face (doggieface@aol.com), October 21, 2001.

THIS IS NOT A FLAME.

The moral of the story being don't believe everything you read on the web. There is something wrong with their rating for the 300 F4L IS, because I can assure you that it is better than 3.4. I have two other rated lenses (24-85...3.1, 70-200 F4L...4.1), and the 300 F4L IS is very definately on a par with the 70-200 F4L, if not better than. I have also compared the 300 F4L IS to my father's 100-400L IS (which scores 3.6 on photodo), and the 300 is the better lens (although both are good). Sometimes you just need to apply a "reality check" to things, and think "Is a 4X zoom REALLY going to be as sharp as a good quality prime?". I don't think so.

So, I personally will go with experience, and say that the 300mm F4L IS is a very good lens. Now, if we look at the use of the two lenses around the 600mm length with the appropriate teleconverters, both have similiar sized objective elements, and thus their resolving power will be in a similar area. As I said initially, the 400 F5.6 + 1.4X TC is probably the sharper, but I think that the 300 F4L IS + 2X mk II isn't going to be too bad, and it makes a more useful set of lenses if you have both TCs: 300 F4, 420 F5.6, 600F8, 840 F11, rather than 400 F5.6, 560 F8, 800 F11 and 1120 F16. Around 600mm F8, IS is really going to help.

What it comes down to, I guess, is that either way would be hard to go wrong.

-- Isaac Sibson (isibson@hotmail.com), October 21, 2001.

Actually, 3.4 is a very good score, just not as nice as 4.3 or 4.4! The EF 300 4L USM vs EF 300 4L IS USM has been discussed a lot during the last few years, especially this score. Most folk who have used both lenses say the difference in optical quality is small and prefer the benefits of IS over a little optical quality.

I would love to own the IS version but not bad enough to go to the trouble and expense of selling my non-IS model and buying a new lens. However, IS would steady my tripod in the 30 MPH trade winds that blow everyday...

I wonder how many samples of the EF 300 4L IS USM Photodo tested? Perhaps they tested one or more early models that were below average. I've owned 2 or 3 copies of several Canon lenses and have noted both optical and mechanical variations. Even color seems to vary (due to different people applying lenses coatings?). Most are ok but slightly different, and a few are exceptional or crap.

-- Puppy Face (doggieface@aol.com), October 21, 2001.

I'd agree that there is a lot of sample variation. This is the same with anything. But, my main point, other than the 300 F4L IS not being as different to the 300F4L as the ratings suggest, is that for such reasons, photodo ratings need taking with a pinch of salt.

-- Isaac Sibson (isibson@hotmail.com), October 21, 2001.

Thanks for the feed back Guys. With regards to one of the comments made by Isaac. Would IS still work with a 1.4x & 2x stacked?

-- Jason Eadie (jason_eadie@hotmail.com), October 21, 2001.

I have a 300/f4(non IS)lens (probably my favourite lens), that I have used fairly extensively with a 2X TC with my EOS 3. Although not as good as with the 1.4X TC, the results are quite acceptable. One cannot really fault the photos for sharpness, my feeling was however that the results were better with contrasty scenes, and that the photos in some instances lacked a bit of contrast. Because of this I have recently bought a 500mm/f4.5 lens to provide me with this extra lenght. I would certainly continue to use the 300mm with the 1.4X TC, but would only use the 2X TC in an emergency if I do not have the 500 with me.

Of interest, I have also used the 300mm with both converters stacked together (still autofocussing with my EOS3) and was amazed at the results, which were not noticably different from the results with only the 2X TC.

-- Koot Marais (kma@telkomsa.net), October 22, 2001.

Beware that you will need 2X mk II in order to be able to stack the TCs. However, the reported aperture will (I think) not be correct, as the teleconverters themselves are not TC compatible in terms of the electronics (although the mkII version of the 2X now allows the 1.4X to be fitted to it physically). This shouldn't cause any great problem however...just remember to take account of it in manual mode or aperture priority, and if you record exposure data.

The upshot of this also is that the EOS 3 and EOS 1V will still attempt to AF with the centre point (and may succeed on well lit days), but if this works at all, regard it as a bonus, don't rely on it.

However, IS should indeed work with stacked TCs, with newer EOS bodies. Look at the well-publicised lists of IS/TC/Body incompatibilities. Any body that has no problem with IS at small apertures (anything from the EOS 1N hence) should be ok. I haven't tried this though, so I'm not 100% sure. I think Art Morris has said something about TC stacking on his website (www.birdsasart.com), but I'm not entirely sure.

-- Isaac Sibson (isibson@hotmail.com), October 22, 2001.