Need wider aperature; what would you do?

Spent the weekend at the horse show shooting other member of my team. I mostly shot with the 50D and the 70-200 f/4L IS between 130mm and 200mm. I found it to be a little too slow for indoor shooting which I expected. What I didn't count on was the distracting backgrounds outdoors and the inability to separate the subject from them. I really like the weight, feel and image quality of this lens. Now I'm trying to decide what to do. I can spend about 500-600 bucks. That means I could sell the f/4L IS and buy a used f/2.8L non-IS, buy a new Sigma 70-200 f/2.8 OS or keep the f/4L and buy a used 200 f/2.8L prime. I think the perfect solution for me would be the Sigma 120-300 f/2.8 OS but, I can't swing that right now. Input??

Bob

If I were you I would sell the Canon 70-200mm f/4L and buy a Canon 70-200mm f/2.8L. Unless your going to use it hand held then I would spend a little more and buy a used Canon 70-200mm f/2.8L IS.

Take Care,
Cheers, Patrick

I don't think f/2.8 is going to solve your b/g problem. You either: need to get closer to the subject, or get shots with more distance between the subject and b/g. 2.8 isn't the magic background eraser/blurer, and although it will help.. the difference between f/4 and f/2.8 isn't going to save you like you might think. The 70-200 f/4L IS does a pretty decent job of separating the subject/background, with very nice bokeh..and compression. As for light, well, do you think the extra stop will make THAT big of a difference? Only you can answer that. You might be better with the 135L.

Where are 70-200 F2.8 IS on e-bay slightly above $1500 for CONUS only.

Definitely go with the Sigma 70-200 2.8 OS over the IS I.

dachness wrote in post #14361673
Definitely go with the Sigma 70-200 2.8 OS over the IS I.

Why? What makes the Sigma a better choice than a Canon IS I? The warranty would be nice but is the IQ as good or better? I've read every page of the sample photo thread for the Sigma and I find it inconclusive. I would like to see "the digital picture" put this lens up on the comparison charts.

Bob

From reading the comments of the Sigma OS thread. The lens is often compared to the IS II it is softer wide open but becomes equal once stopped down a little. If I didn't purchase the IS II I would have gone with the 2.8 OS. I personally would rather have the 70-200 2.8 non-IS than the IS I for IQ purposes.

The F4IS IQ is better than the IS I and the Sigma is about the same when stopped down. I believe that the Sigma has better IQ than the IS I. I have not personally tested either so take it for what it's worth.

https://photography-on-the.net …p?p=14361769&po​stcount=27

I think the Sigma gets compared to the MK2 because that is the newest Canon. Usually said to be less sharp, than the Canon. Some say better than MK1 and some don't. The MK1 one was the go to lens for those that needed the FL ans f2.8 aperture. It did not get bad just because the MK2 came out. I think my copy is sharp. I don't think you would go wrong with ether. But everyone says the MK2 is the best. If I were buying again personally I would still get the MK1 over the Sigma. I do like sigma, but I still think the Canons are better built, focus fast, hold their value better, overall for a given equivalent FL and apertures I just like a majority of Canon lenses better.

Either way you pick, I think IS is a fantastic asset. Even when you need action stopping shutter speeds.

1Tanker wrote in post #14361385
I don't think f/2.8 is going to solve your b/g problem. .

I was thinking the same thing at first, but then I noted the OP was using the 50D and also owns a 5D2.

My suggestion would be to get one of the 70-200/2.8 options and then use the 5D2 instead of the 50D. For any situation in which this combination does not require cropping for reach, the effect will be to reduce the DOF a little more than two stops of aperture over where the OP had started from.

Note though if one is at 200mm and cropping hard, then the DOF advantage of the larger sensor is lost and you only get the one stop from the f/2.8.

But the idea of using a 135L instead has a similar problem. It only gives a two stop DOF gain when used at 135mm with no cropping. Crop it to the field of view of a 200mm lens at you are at the same DOF as 200/2.8.

Short of going to something really expensive (120-300/2.8 or 200/2) I think the OP wants a 70-200/2.8 and should use the larger format

JeffreyG wrote in post #14363280
I was thinking the same thing at first, but then I noted the OP was using the 50D and also owns a 5D2.

My suggestion would be to get one of the 70-200/2.8 options and then use the 5D2 instead of the 50D. For any situation in which this combination does not require cropping for reach, the effect will be to reduce the DOF a little more than two stops of aperture over where the OP had started from.

Note though if one is at 200mm and cropping hard, then the DOF advantage of the larger sensor is lost and you only get the one stop from the f/2.8.

But the idea of using a 135L instead has a similar problem. It only gives a two stop DOF gain when used at 135mm with no cropping. Crop it to the field of view of a 200mm lens at you are at the same DOF as 200/2.8.

Short of going to something really expensive (120-300/2.8 or 200/2) I think the OP wants a 70-200/2.8 and should use the larger format

I just sold a Sigma 70-200/2.8 non-OS because the IQ of the canon f4L was so much better. Though the 200/2 would be nice to have, I don't know if it would be the best choice for this situation. I really need a zoom which is why the 200/2.8 is not going to work either. If I could swing it, I'd go for the Sigma 120-300/2.8 OS and use it on the 5DII. That would be perfect except for the slower frame rate. I almost always frame looser and crop in post processing when shooting moving subjects. Too heavy cropping is going to limit me on print size though. Maybe now is the time to let the 50D and a few other things go so I can fund the 120-300 OS.

Bob

120-300 is your best bet on your 5dII imho.

I will say this, I sold my 70-200 F4 IS to fund the sigma 70-200 2.8 OS and have no regrets. Same image quality at F4 with the capability to goto 2.8

Ok, so here's what I'm going to do for now. I just sold the f/4L and ordered a Sigma 70-200/2.8 OS. That gets me one extra stop of separation on the 50D. Any ideas on what I would get if I added a 1.4x TC to this and used it on my 5D? I'm thinking I would get some more separation but a slight loss of focal length.

Bob

Too late I guess because you indicate you already acted. In any event you need to get a good understanding of depth of field and I would suggest you go to http://www.dofmaster.c​om/dofjs.html and play with the online DOF calculator.

Putting some numbers to the comments by "1Tanker"...with your 5d MkII at 180 mm, f/4, subject distance of 20 feet the DOF = .88 feet. Same setup and going to f/2.8 the DOF = .62 feet. As you can see that change from f/4 to f/2.8 only changed the DOF by 0.22 foot or about 2-1/2 inches!

Now lets look at a subject distance of 50 feet, again with the 5DMk II and the lens at 180mm...

5d MkII 180 mm, f/4, subject distance of 50 feet DOF = 5.6 feet
5d MkII 180 mm, f/2.8, subject distance of 50 feet DOF = 3.95 feet
Now we've gained 1.65 feet or almost 20 inches.

Just a point of comparison, the 50D, at 180mm (setting) and f/4 with subject at 50 feet has a DOF = 3.54 feet compared to the 5.6 feet of the 5D MkII at the same settings. This is the effect of the differing sensor sizes, a consideration you also need to look at with the effective field of view of the two cameras you use.

Thanks for the input John. Not trying to pick you apart but, in order to compare the crop to the full frame you need to normalize the focal lengths. The 50D at 180mm is providing a FOV of a 288mm. In order to compare it effectively, you need to set the 50D to 112mm. The DOF then becomes 9.4 feet.

I would say I have a pretty good understanding of DOF. I've been a serious amateur photographer for over 25 years. I have the DOFMaster app on my phone and I've run the numbers extensively. Realistically, I need the 120-300/2.8 to produce the results I want. That is not going to happen anytime soon.

The thing about DOF is that it is so variable. If a background is just inches outside my DOF it may appear to be well within focus until you zoom in and get critical. In general, at the horse shows, I am shooting subjects that are 8-9 feet in depth and are 75-300 feet away. My backgrounds range from 400 feet to 1500 feet away. There is no calculator that I know of that can tell me relative amount of blur for OOF background by distance beyond DOF.

My experience has shown me that although one stop may not provide much separation a couple feet beyond the DOF, it does provide better background blur the further away the background happens to be.

So, what I can calculate is this (@100 feet):
50D + 200mm @ f/4 DOF=11.54'
5D + 200MM @ f/2.8 + 1.4x DOF=6.5'
5D + 300mm @ f/2.8 DOF=5.7'

That's a big difference; and it will be even bigger 500 feet beyond the subject. It may not be exactly what I want but, it is much closer.

Bob

Ok, making a correction (I think) to what I just posted above. My DOF app does not seem to take into account the aperature change when selecting a TC. DOF for the 5D + 200mm @ f/2.8 + 1.4x is actually 9.26'. So still an improvement but not as big. We'll see what happens in the real world.

Bob