300mm f2.8 L IS + extender questions

I'm looking to buy a 300L is mk1 and I also have my eyes on 2 extenders but I'm not sure which one would be best, they are 1.4x mkii & 2.0x mkii, both in the same condition, same age and same price.
I will be using it on a 7d2 for sport, mostly Rugby, Soccer, Cricket and any other sport that demands good reach

I have the 300 F2.8 L IS as well as a 7D2 myself. It is simply an excellent lens.

As to extenders I didn't find much difference between the Canon 1.4 Mk 2 or 3. I THINK the AF on my 1DX might be quicker (didn't have the 7D2 then) with the Mk3 but I was probably imagining it!

With the 2 x extender I would go for the Mk3, I had the Mk2 but was never happy with it. On the other hand the Canon 2 x Mk3 gives very good images with this lens. When I first bought my 2 x Mk3 I had the Canon 600 F4 L IS so I could compare performance at 600mm directly. The 300 F2.8 + 2 x can be surprisingly close to the 600 in good to ideal conditions, in less than ideal conditions then the 600 scores - as you would expect.

When I owned the 300 f/2.8L IS I used Canon's 1.4X & 2X MKII extenders quite a bit. The nice thing about them is you could stack the converters and get 840mm @ f/8.

Since then I purchased the MKIII extenders (I still have the 1.4X MKII as well.) The image quality is a little better with the new 1.4X but there is a big difference between the 2X converters. The newer converters also seem to pair better with Canon's MKII lenses.

The downside is you can no longer stack the new ones directly together.

For the long term I'd get the MKIII extenders.

Tapeman wrote in post #18042863
When I owned the 300 f/2.8L IS I used Canon's 1.4X & 2X MKII extenders quite a bit. The nice thing about them is you could stack the converters and get 840mm @ f/8.

Since then I purchased the MKIII extenders (I still have the 1.4X MKII as well.) The image quality is a little better with the new 1.4X but there is a big difference between the 2X converters. The newer converters also seem to pair better with Canon's MKII lenses.

The downside is you can no longer stack the new ones directly together.

For the long term I'd get the MKIII extenders.

You can just add an extension tube between them for stacking. (you don't lose infinity focus if you consider the moon infinity)

Milutiche wrote in post #18042522
I'm looking to buy a 300L is mk1 and I also have my eyes on 2 extenders but I'm not sure which one would be best, they are 1.4x mkii & 2.0x mkii, both in the same condition, same age and same price.
I will be using it on a 7d2 for sport, mostly Rugby, Soccer, Cricket and any other sport that demands good reach

The way that appears to be common sense to me is that you definitely want to get the 1.4 extender, no matter what. Then the only question is whether to also get the 2.0 extender as well. I's typically not an either/or thing. Rather, it is a "one, or both?" question.

By the way, you are wise to be considering the discontinued version 2 Canon extenders. There is no need to buy the much more expensive version 3 extenders - the version 2 Canon extenders will work quite well. I use them on my 400 f2.8 IS version 1, an they work as well as one could wish. I have the mark 3 2.0 extender, but it isn't any better at all than the mark 2 version. But that would probably be different if I were using them on newer lenses.

.

The 1.4 you'll enjoy especially with that lens.

I nearly never used my 2x; the IQ impact is substantial, and you loose 2 stops.