70-300 IS L vs S120-300

I know that these lenses are more than a bit different
size, aperture, weight, focal length (slightly), price
all very different

what is very similar is that both are highly praised for their IQ
and the overlap of 120-300 focal range

but can anyone note a difference in IQ in the overlap range?
if I **KNOW** that I will have good light...

can I "get away" with the lighter lens?

ceriltheblade wrote in post #17247475
I know that these lenses are more than a bit different
size, aperture, weight, focal length (slightly), price
all very different

what is very similar is that both are highly praised for their IQ
and the overlap of 120-300 focal range

but can anyone note a difference in IQ in the overlap range?
if I **KNOW** that I will have good light...

can I "get away" with the lighter lens?

In a word, yes. Both have great IQ and the differences, if any, are very minor. I've owned the 70-300L and I now have the Sigma 120-300 Sport.

Here's an IQ comparison page. You'll see at matching range and aperture there is really no difference.

One thing to consider is that the Sigma can be used with a 2x extender giving you 600mm at f5.6. Check the lens sample thread and you'll see that the Siggy with the 2x also has great IQ. Of course you're talking about a huge price difference, so the extra reach would have to be worth the cash outlay to you.

That weight difference is something to consider seriously. You can handhold the 70-300L all day long. That Siggy wears on your arms very quickly. If you're a tripod/monopod shooter, that may not matter.

And I haven't seen any detailed comparisons (although I'm sure they're out there), but my gut feeling is that the IS on the Canon is a bit better than the IS on the Siggy. But that's just my opinion. YMMV

there is never (just about) reason to get a 2.8 lens, if you "Know" you will be shooting it at f4-5.6. so if you know that you dont need the extra stops, there are many reasons you should go with the canon L.

M_Six wrote in post #17247542
In a word, yes. Both have great IQ and the differences, if any, are very minor. I've owned the 70-300L and I now have the Sigma 120-300 Sport.

Here's an IQ comparison page. You'll see at matching range and aperture there is really no difference.

One thing to consider is that the Sigma can be used with a 2x extender giving you 600mm at f5.6. Check the lens sample thread and you'll see that the Siggy with the 2x also has great IQ. Of course you're talking about a huge price difference, so the extra reach would have to be worth the cash outlay to you.

That weight difference is something to consider seriously. You can handhold the 70-300L all day long. That Siggy wears on your arms very quickly. If you're a tripod/monopod shooter, that may not matter.

And I haven't seen any detailed comparisons (although I'm sure they're out there), but my gut feeling is that the IS on the Canon is a bit better than the IS on the Siggy. But that's just my opinion. YMMV

I think the 1.4X and the 2x telecoverters are the main difference. If you are shooting wildlife, being able to shoot at 600mm is extremely nice.

I have the 70-300L and it's a great lens..... but I often need something longer. I added a used 400 f/5.6L for this reason... but 600 mm would be better. I can use the 1.4X teleconverter but only for stationary targets and I had to buy the Kenko instead of a Canon because it's non reporting and my current camera won't auto focus at f/8.

without the hood the 70-300l fits in my jacket pocket. it's even more packable the the 70-200l f4 IS.

the sigma is a monster and it's expensive and it will never AF with the consistency of a canon L lens.

... mostly true, except maybe when the light gets low. 2.8 vs 5.6, 4x more light at 300mm.
But in good light the Canon's AF is much faster. As for accuracy, Sigma's fast tele zooms are pretty much as good as Canon's in my experience (as opposed to some fast primes). Both my 70-200 2.8 OS and 120-300 2.8 OS AFs very accurately, I don't even need MFA on my bodies.

I always find this type of question interesting because they pretend the lens IQ is the only thing that will affect the image produced. No mention of whether it will be for hand holding ONLY, or to shoot moving targets which means PERFECT panning skills, or even if the intended use requires slow shutter speeds like needed for prop blur or wheel / tire / background blur as in motorsports photography. Unless the question relates to shooting from a very stable tripod or fixed mount technique is more important than a small difference in IQ as reported by lab tests.

thanks for all the comments above.

_cicopo_ thanks for your comments as well. Of note, in the OP, I did give a nod to the difference in the weight and the price....

the basis of this question is mostly because I am trying to figure out my best strategy for the longer lenses. I am interested currently in shooting my son's soccer play from the sidelines - and in my assessment of where I can shoot from and the light qualities - I can do with 300mm focal length.
I have been interested in the s120-300 because it can take the TCs very well (as evidenced by Gabe's wonderful samples in the relevant threads) and because it has great IQ. I recently got interested in the 70-300L because of the rave reviews it got - though it is much much slower (and lighter and cheaper). I have looked at the Tamron 150-600, and I have been following with anticipation also the S150-600 sport - but I am not sure that I will need the 600 focal length.

Since it is on the soccer pitch- I **CAN** bring a tripod (though there is a benefit for use of hand holding) and since it is daytime I will have good light. Since it is soccer - I won't need panning. And if I ever need panning - I will have to learn how to pan (i have never found a need for it in my own photography) - so this isn't a main issue for me. Since it is my son, I really want to capture him the best I can (within reasonable costs of the lens)....

So I return to the issue: would the IQ of the two lenses be comparable? There have been various comparisons of the 70-200 f4IS with the 70-300 IS L and the 70-300 has fared extraordinarily well. But for me - the big "bad boy" that I want it to compare to is the S120-300!

i hope this doesn't come off too snarky...because it wasn't meant to be. Just clarifying my OP.

Check that comparison page I linked. Virtually no difference in IQ. Nothing you'll see in actual photographs anyway. If you're going to be taking lots of shots at a soccer game, you'll want a monopod if you go with the 120-300. You won't necessarily need one with the Canon. With the $$$ savings you see by getting the Canon, you can buy an SL1 and stick a shorter lens on it for closeups on the sideline. The SL1 with the 40mm pancake or 35mm f2 IS will weigh next to nothing hanging around your neck. Maybe even pick up the soon-to-be released 24mm f2.8 pancake.

Lots of options here. But the big point is, IQ should not be the deciding factor between the two lenses. It's so close it won't matter.

ed rader wrote in post #17248185
without the hood the 70-300l fits in my jacket pocket. it's even more packable the the 70-200l f4 IS.

the sigma is a monster and it's expensive and it will never AF with the consistency of a canon L lens.

The 120-300 I owned had great AF. It never limited my use of the lens.

The shots you'll get at 2.8 will blow away the shots from the 70-300. Subject isolation with a 2.8 lens is why professionals shoot with fast lenses.

I agree with others who say IQ is probably not the deciding factor here. You're considering two great lenses, both of which are capable of producing outstanding images. One is f2.8, the other is not. You're not a professional photographer, you're someone who wants great images of your kid doing sports.

Do you need f2.8? Will you use it, or will you stop down the lens? Is f2.8 capability worth the considerable extra weight?

You're going to use the lens to photograph your son's soccer games. Is this the only thing you'll use it for, or will you also want it for other activities with your children, such as trips to the zoo, outings to the park, parties, school events, etc.? If you're going to use the lens for other family activities, the weight should absolutely be a consideration.

Speaking as someone who's been in your shoes, chose a heavy lens and eventually sold it for a lighter one (because I hated carrying it and didn't like shooting with a monopod), I'd strongly suggest renting the Sigma first, to see if you actually enjoy using a large, heavy lens. This will make your decision a lot easier.

If it helps, I had a similar dilemma to yours: I owned a much-loved 70-200 f4 IS that was a bit too short for the sport I enjoy shooting. Having previously tried the experience, I knew I didn't want a heavy lens and I knew I could live without f2.8 capability. I chose the 70-300L and have absolutely no regrets - none. As Ed Rader pointed out, it's small and compact enough to take everywhere, the AF is second to none, and the images it produces are outstanding. On paper it doesn't look like much: but in real life it's a terrific piece of equipment.

You may think you won't need to pan when shooting Soccer but I'll bet you'll be panning soon enough. Fortunately you get to use fast shutter speeds. It's a running & kicking etc sport & players move about, even young ones.

if you're not going to take advantage of the benefits of the 120-300mm...i don't know why you'd want to lug it around