Considering trading my Canon 70-200 f4 for Tamron f2.8 (both non-is)

What are the pros and cons?

I gain 2.8 which helps me keep my shutter speed up, I guess gives me better subject separation not that that's a problem with the f4.
I lose AF speed I assume, not a killer for me, the fastest thing this is shooting is my 4 year old and I'm ok with a low keeper rate.
I may lose image quality??? how much how bad?

What aren't I considering? List your general thoughts on this idea, please.

It kind of sounds like you 're ok with what you have, and you've identified possible negatve aspects that you'd be ok with - so one has to ask - what has precipitated you thinking about making the trade?

Because of the Non-IS (and 4 year olds) I need to keep a 200 or faster shutter speed. Being able to drop to f2.8 will allow my ISO to stay usable in darker situations. That's my main reason for considering the switch.

You could add a flash to help the issue. Or increase your ISO.

I wouldn't do it as the focusing speed is going to be a bigger issue than you think.

I have a Tamron 70-200 2.8. Its the one with the older style AF motor. Its loud, clunky and slower to focus than Canon USM lenses. Its not usually a problem if you are semi pre focused, in fact it snaps to focus pretty fast to be honest. But if you fail to lock the focus, it will hunt back and forth all over the place and sound like a cordless drill while doing so. Image quality is good to fantastic, but I did have to dial in a bit of adjustment on my body. Its ok wide open, but not the best. Stopped down to 3.2 or even 4 and it gets pretty sharp. Honestly, I think you would get better results with the Canon you have and just add a bit of fill flash or up the ISO.

I don't think a flash helps, I still have to keep my shutter speed up to account for camera shake (using the 1/FL rule). (Correct me on this if the freezing effect of flash makes the rule more flexible).

Hearing that I'd need to stop down to f4 to get the Tam sharp is a bit disappointing but when I needed the f2.8 it'd be there. And if it gets me from ISO3200 to ISO1600 it goes from a nearly terrible to nearly good picture.

dont get me wrong, wide open its not bad. Its just not cream of the crop. Most lenses wide open are not at their sharpest, this one is no different. I use 2.8 all the time.
here's a link to an image I shot with the Tamron 70-200 at 2.8

ive used the tamron.... and I hated it. AF was bad, really soft, and the af/mf switching is such a pain because it'll switch to MF all the time.

i have used it extensively and never once had it switch to MF when I didnt want it to. Dont hold it there, problem solved. I agree the AF is pretty bad, but its no worse than a kit lens.

gnome chompski wrote in post #16251752
i have used it extensively and never once had it switch to MF when I didnt want it to. Dont hold it there, problem solved. I agree the AF is pretty bad, but its no worse than a kit lens.

If kit lens we are talking about the 55-250? Because I don't think those two compare. I would compare to the 70-200 f4

travisvwright wrote in post #16250551
I don't think a flash helps, I still have to keep my shutter speed up to account for camera shake (using the 1/FL rule). (Correct me on this if the freezing effect of flash makes the rule more flexible).

Hearing that I'd need to stop down to f4 to get the Tam sharp is a bit disappointing but when I needed the f2.8 it'd be there. And if it gets me from ISO3200 to ISO1600 it goes from a nearly terrible to nearly good picture.

Not with a flash, the flash duration is tiny compared with your shutter speed. It will be ok that is unless you get into fill flash etc.

For me, id keep the Canon lens and add a speedlite.