More reach

[dhr90]

Struggling to work out where was best for this topic. I know its been covered numerous times before, but I'm after more reach than 200mm of my 70-200 on my 7D. It would be used primarily for motorsports, airshows and wildlife

Budget is around £1000 which gives me options of:
2x tele converter iii
Canon 100-400mm
Tamron 150-600mm
Sigma 150-500mm
Anything I've missed?

I have debated the Canon 400mm f5.6, but at that sort of focal length I highly doubt I would get along with a prime.

I have played with the Tamron, but struggled to hold it steady enough about 400 even on a monopod, looking back the shutter speed was just far too low, I've seen on here some excellent images shot with it. To use it above 350/400mm I'd need to use a tripod I think, something I won't always carry as mine is fairly heavy.

I demo'd a 2x converter today and the autofocus felt faster, it was a lighter rig (although the weight felt more than I'm used to with the lens being that bit further from the camera, it was better than the Tamron where the weight moves as you zoom), and is easier to carry than 2 separate, heavy lenses. It's also much cheaper! ;D

Haven't tried the Sigma, I seem to hear good and bad things about it so I'm not sure what to think, the price appeals to me, but its image quality I'm after, then probably weight and thirdly price.

Something I'm uncomfortable with is the focal length and thus the ISO required to get photos, when demoing the tamron lens and Canon converter my camera has gone to ISO 3200 and still captured dark results, it is more noise than is acceptable to me and I'd not want to use whatever I bought. Yes the shop was reasonably well lit, but far from many of the lighting conditions outside in daylight, however better than a wooded area for some wildlife or a tree lined racetrack.

I've thought about the 1.4x tele converter, but having used 300mm previously on another camera I just don't think 280mm would be enough, even though its more than I have now.

I guess I need some advice, reassurance and maybe out of the box thinking. I'm probably a bit averse to spending the money, especially when I won't get to use it more than 10 times per year.

Maybe I should save my money and just crop images until I have the time to use whatever the solution is?

 

[Random Orbits]

Sounds like there isn't much of a solution in your case. The 70-200L II + 2x, 100-400L, 400L and the tamron 150-600 are all at f/5.6 at 400mm and the Sigma 150-500 is at f/6.3 at 400mm, so none of your candidates would allow you to use lower ISO. Faster lenses are much more expensive and heavier (300 f/2.8 IS II or 400 f/2.8 IS II).

Perhaps another way is to get a 5DIII and the Tamron 150-600. The Tamron will give you the length you need, and the FF camera will give you a couple stops improved high ISO performance. Higher ISO will let you increase the shutter speed to avoid using a monopod/tripod.

 

[jrista]

At the moment, I don't think you could really do better than the Tamron 150-600 as far as focal length goes. For the price, it's quality can't be beat. It's barely more than twice the cost of a 2x teleconverter, and it will get you considerably more focal length, which means much greater magnification (relative subject area in the frame at 600mm is 2.25x greater than with the 70-200+2x TC...even if the 600 is a tough soft in comparison (which I doubt), your packing so many more pixels on subject that it's still way worth it to get the Tamron.)

Regarding hand-holding technique, that improves with time. It does take some skill to learn how to hold a long lens and get stable shots, with or without image stabilization. You should get used to it at either 400mm or 600mm, regardless of which option you choose.

As for ISO, you will indeed need to be using higher ISO settings at those apertures. Your losing a stop or more of light, so if you used to hover around ISO 1600 at 200mm, then it's no surprise that your around ISO 3200 at 400/600mm.

Finally, given the subjects you shoot, with the exception of wildlife (which is often largely stationary), you might actually find that fast aperture is actually more important than focal length. Motorsports and airshows both involve fast moving subjects. For both cases, I would offer that a 7D with 70-200 f/4 is probably the worst combination. You really want bigger pixels and the fastest lens you can get your hands on...like the 70-200 f/2.8 (I don't know which 70-200 you have). I'd offer that physically getting closer for motorsports is better than sacrificing aperture for longer focal length. As for airshows, I know a couple guys who do that almost exclusively. Both own the EF 300mm f/2.8, and one owns the EF 200mm f/2. Those are their staple lenses. They rarely go to longer focal lengths (and the one often favors the 200mm) because they need the wider field to include the whole plane and enough white space around it to make a pleasing composition.

So, assuming you currently have the 70-200mm f/4 lens, I would actually offer that getting the 70-200mm f/2.8 II lens is probably another alternative, and one that might support your motorsports and airshows better than a longer focal length. Those subjects just move so much faster on a consistent basis than wildlife does. If you really needed to, you could slap the 2x TC onto that, and you would have a 400mm f/5.6 lens, albeit one that doesn't quite offer the same IQ as the 400/5.6 prime or 100-400. If you primarily do wildlife, and motorsports/airshows are a distant second, then I'd get the Tamron 150-600, and just work out your hand-holding skill (as it will get better over time.)

 

[neuroanatomist]

The only two options I'd consider (other than the Tamron 150-600 you tried and eliminated) are the 100-400L and the 2xIII (and the latter only because you indicate the 70-200/2.8L IS II in your sig, IQ takes a big hit with any other 70-200). FWIW, I have the 100-400, 70-200 II, and both MkIII TCs.

Between those two, the IQ is equivalent (lab tests give a very slight edge to the 100-400 at 400mm, but it's not a big enough difference to affect real world shots). The AF performance is similar, too (the 70-200 + 2x focuses slower and hunts more than the bare lens, putting it on par with the older, slower lens). IMO, the 100-400L handles better - shorter (when retracted), better balanced, no TC to mount. The 70-200+2x is cheaper, and gives you the option of a shorter f/2.8 zoom when the light gets dim without having to carry two white zooms.

Personally, if I'm going out to shoot mostly at 400mm, I take the 100-400. If I'm going out for more general shooting and want an opportunistic 400mm, I take the 70-200 and throw in the 2xIII.

 

[expatinasia]

A 300L f/4.0 IS would give you a bit more reach and with a 1.4X takes you to 420.

But, as jrista said, the Tamron may be your best option.

 

[dhr90]

Sounds like there isn't much of a solution in your case. The 70-200L II + 2x, 100-400L, 400L and the tamron 150-600 are all at f/5.6 at 400mm and the Sigma 150-500 is at f/6.3 at 400mm, so none of your candidates would allow you to use lower ISO. Faster lenses are much more expensive and heavier (300 f/2.8 IS II or 400 f/2.8 IS II).

Perhaps another way is to get a 5DIII and the Tamron 150-600. The Tamron will give you the length you need, and the FF camera will give you a couple stops improved high ISO performance. Higher ISO will let you increase the shutter speed to avoid using a monopod/tripod.

Sadly the 5DIII + Tamron would cost about £2500-£3000. As much as I would like to one day go full frame, right now I just cannot afford it.

At the moment, I don't think you could really do better than the Tamron 150-600 as far as focal length goes. For the price, it's quality can't be beat. It's barely more than twice the cost of a 2x teleconverter, and it will get you considerably more focal length, which means much greater magnification (relative subject area in the frame at 600mm is 2.25x greater than with the 70-200+2x TC...even if the 600 is a tough soft in comparison (which I doubt), your packing so many more pixels on subject that it's still way worth it to get the Tamron.)

Regarding hand-holding technique, that improves with time. It does take some skill to learn how to hold a long lens and get stable shots, with or without image stabilization. You should get used to it at either 400mm or 600mm, regardless of which option you choose.

As for ISO, you will indeed need to be using higher ISO settings at those apertures. Your losing a stop or more of light, so if you used to hover around ISO 1600 at 200mm, then it's no surprise that your around ISO 3200 at 400/600mm.

Finally, given the subjects you shoot, with the exception of wildlife (which is often largely stationary), you might actually find that fast aperture is actually more important than focal length. Motorsports and airshows both involve fast moving subjects. For both cases, I would offer that a 7D with 70-200 f/4 is probably the worst combination. You really want bigger pixels and the fastest lens you can get your hands on...like the 70-200 f/2.8 (I don't know which 70-200 you have). I'd offer that physically getting closer for motorsports is better than sacrificing aperture for longer focal length. As for airshows, I know a couple guys who do that almost exclusively. Both own the EF 300mm f/2.8, and one owns the EF 200mm f/2. Those are their staple lenses. They rarely go to longer focal lengths (and the one often favors the 200mm) because they need the wider field to include the whole plane and enough white space around it to make a pleasing composition.

So, assuming you currently have the 70-200mm f/4 lens, I would actually offer that getting the 70-200mm f/2.8 II lens is probably another alternative, and one that might support your motorsports and airshows better than a longer focal length. Those subjects just move so much faster on a consistent basis than wildlife does. If you really needed to, you could slap the 2x TC onto that, and you would have a 400mm f/5.6 lens, albeit one that doesn't quite offer the same IQ as the 400/5.6 prime or 100-400. If you primarily do wildlife, and motorsports/airshows are a distant second, then I'd get the Tamron 150-600, and just work out your hand-holding skill (as it will get better over time.)

I use a 70-200 f2.8 IS II. Not the f4 model

So if I drop one stop of aperture, I bump up one notch of ISO? I'm looking through my library and trying to gauge the ISO's, apertures and focal lengths used and what I could wish for.

Of the events I've been to, most of the time 200 is more than enough, but as a spectator there is only so close you can get to the track, and catch fencing does rather limit your view a lot of the time.

Airshows, again 200 is more than enough a lot of the time, however there are times when a bit more reach for the smaller planes (biplanes, spitfires etc), or when they are manoeuvring further away would be useful.

Wildlife is third on my list after motorsport and airshows.

The only two options I'd consider (other than the Tamron 150-600 you tried and eliminated) are the 100-400L and the 2xIII (and the latter only because you indicate the 70-200/2.8L IS II in your sig, IQ takes a big hit with any other 70-200). FWIW, I have the 100-400, 70-200 II, and both MkIII TCs.

Between those two, the IQ is equivalent (lab tests give a very slight edge to the 100-400 at 400mm, but it's not a big enough difference to affect real world shots). The AF performance is similar, too (the 70-200 + 2x focuses slower and hunts more than the bare lens, putting it on par with the older, slower lens). IMO, the 100-400L handles better - shorter (when retracted), better balanced, no TC to mount. The 70-200+2x is cheaper, and gives you the option of a shorter f/2.8 zoom when the light gets dim without having to carry two white zooms.

Personally, if I'm going out to shoot mostly at 400mm, I take the 100-400. If I'm going out for more general shooting and want an opportunistic 400mm, I take the 70-200 and throw in the 2xIII.

I suspect that not wanting to go above ISO 1600 on my 7D would limit me with the Tamron lens, maybe I could demo it again outside in daylight rather than in a store some time.

The last sentence is very interesting and a way of thinking I hadn't considered before, looking at it that way the 2xIII is likely to suit me more I think. Especially as, mentioned above, motorsport and airshows rarely require too much beyond 200/300mm.

A 300L f/4.0 IS would give you a bit more reach and with a 1.4X takes you to 420.

But, as jrista said, the Tamron may be your best option.

I hadn't considered that approach. 2 lenses for the price of not much more than 1. However it is about £300 more than the Tamron route. And again, weight of carrying that and a 70-200. Maybe in the future a 300 f4 would make its way into my kit, but I think I'd like a cheaper way of finding out if I could get along with shooting with a prime (I'd like ot try the nifty fifty or shorty forty, but they are focal lengths I just don't use 98% of the time.

I think the solution here is to win the lottery and buy all the focal lengths I desire and a van to carry them all with me ;D

 

[wildlifeandmore]

Tough decision...I would look at a pre owned (sounds better than used) Canon 300mm f/4L IS and a 1.4xii/iii. Then I would take the camera, lens and 1.4x to a local camera shop to have them all adjusted to your camera body. A good shop will have an experienced person with perfect studio lighting and equipment. Worth spending a few bucks on if you not experienced with this. I would not be shy of getting an older Canon 300mm 2.8L that looks like crap cosmetically either. As long as the glass is good. Put a lens coat on it maybe? Tough to find though...

Hope this helps.

 

[jrista]

I use a 70-200 f2.8 IS II. Not the f4 model

Ah! Sorry! At least you do have the f/2.8 II, though...that's a great lens!

So if I drop one stop of aperture, I bump up one notch of ISO? I'm looking through my library and trying to gauge the ISO's, apertures and focal lengths used and what I could wish for.

You either notch ISO up a stop, or, if you have shutter speed to spare, you reduce shutter speed by a stop. I don't shoot motorsports...I do shoot my friends model airplanes in flight every so often. Owning the 7D myself, with it's smaller pixels, it's tougher to get away with reducing shutter speed unless you specifically want some motion blur. So generally speaking, every stop of aperture lost usually means a stop increase in average ISO used.

Of the events I've been to, most of the time 200 is more than enough, but as a spectator there is only so close you can get to the track, and catch fencing does rather limit your view a lot of the time.

Airshows, again 200 is more than enough a lot of the time, however there are times when a bit more reach for the smaller planes (biplanes, spitfires etc), or when they are manoeuvring further away would be useful.

Wildlife is third on my list after motorsport and airshows.

Since wildlife is the tertiary activity, then I have another option for you. I don't know what your budget is, although it sounds like $2500 may be around the limit? I have been subscribed to CanonPriceWatch.com for a few years now. I have a number of alerts set up in their system. Over the last couple of months, I've been getting a LOT of alerts about Canon's Mark II telephoto lenses. Several times over the last week and a half, I've been alerted of USED Canon EF 300mm f/2.8 L II lenses clocking in at ~$2700-2800. Given the list price for that lens, that is a superbly good deal!

For your motorsports and airshows, I really don't think you could do better than a 300mm f/2.8 II. It's eminently hand-holdable, the big aperture is ideal for the kind of fast moving subjects you shoot, and it easily adapts to 420mm f/4 with the 1.4x TC, which is still well within the realm of usability. If you really need it, you can always slap on the 2x TC for 600mm f/5.6 performance. I rented this lens a couple times a year and two years ago. I used it with both teleconverters. IQ with both was EXCELLENT. Even with the 2x TC, it performed as well or better than my 100-400mm lens, and the boke was always superior, regardless.

For $2700, even though that might be a bit beyond your desired budget, I really don't think there is a better lens for the kind of subjects you photograph. These deals come an go, and I've seen the lens sell used for as low as $2399. I'd go to CanonPriceWatch, find that lens, and set up some alerts for the used price range you would find acceptable (I'd say $2300-$2900 is very good for used), and take advantage of the next deal. New, this lens costs about $7300, and new deals rarely go below about $5500. I myself will probably be picking up a used copy, so long as it was well cared for, next time a $2700 deal rolls around. It's just too cheap to pass up.

 

[Maximilian]

The only two options I'd consider (other than the Tamron 150-600 you tried and eliminated) are the 100-400L and the 2xIII (and the latter only because you indicate the 70-200/2.8L IS II in your sig, IQ takes a big hit with any other 70-200). FWIW, I have the 100-400, 70-200 II, and both MkIII TCs.

Between those two, the IQ is equivalent (lab tests give a very slight edge to the 100-400 at 400mm, but it's not a big enough difference to affect real world shots). The AF performance is similar, too (the 70-200 + 2x focuses slower and hunts more than the bare lens, putting it on par with the older, slower lens). IMO, the 100-400L handles better - shorter (when retracted), better balanced, no TC to mount. The 70-200+2x is cheaper, and gives you the option of a shorter f/2.8 zoom when the light gets dim without having to carry two white zooms.

Personally, if I'm going out to shoot mostly at 400mm, I take the 100-400. If I'm going out for more general shooting and want an opportunistic 400mm, I take the 70-200 and throw in the 2xIII.

I totally agree here with neuro.
And for the choice of the OP I would recommend the 2x TC to dhr90, because it gives you a more flexible setup and saves you some money compared to the 100-400.
The only other choice IMHO as you felt uncomfortable with the Tamron 150 - 600 would be the 100-400, and only if you

• like the push/pull
• know that you are more often in the 200 to 400mm reach
• don’t like the handling of the 70-200 with 2x TC on

I personally love my 100-400. But taking two whites with me would be too heavy and too much volume for me.
Have fun while choosing

 

[dhr90]

Tough decision...I would look at a pre owned (sounds better than used) Canon 300mm f/4L IS and a 1.4xii/iii. Then I would take the camera, lens and 1.4x to a local camera shop to have them all adjusted to your camera body. A good shop will have an experienced person with perfect studio lighting and equipment. Worth spending a few bucks on if you not experienced with this. I would not be shy of getting an older Canon 300mm 2.8L that looks like crap cosmetically either. As long as the glass is good. Put a lens coat on it maybe? Tough to find though...

Hope this helps.

A 300 f2.8 would be intriguing, and maybe just within reach price wise for a battered but optically good one. Heavy though. Think I will put that one to the back of my mind until G.A.S gets a little stronger

I use a 70-200 f2.8 IS II. Not the f4 model

Ah! Sorry! At least you do have the f/2.8 II, though...that's a great lens!

So if I drop one stop of aperture, I bump up one notch of ISO? I'm looking through my library and trying to gauge the ISO's, apertures and focal lengths used and what I could wish for.

You either notch ISO up a stop, or, if you have shutter speed to spare, you reduce shutter speed by a stop. I don't shoot motorsports...I do shoot my friends model airplanes in flight every so often. Owning the 7D myself, with it's smaller pixels, it's tougher to get away with reducing shutter speed unless you specifically want some motion blur. So generally speaking, every stop of aperture lost usually means a stop increase in average ISO used.

Of the events I've been to, most of the time 200 is more than enough, but as a spectator there is only so close you can get to the track, and catch fencing does rather limit your view a lot of the time.

Airshows, again 200 is more than enough a lot of the time, however there are times when a bit more reach for the smaller planes (biplanes, spitfires etc), or when they are manoeuvring further away would be useful.

Wildlife is third on my list after motorsport and airshows.

Since wildlife is the tertiary activity, then I have another option for you. I don't know what your budget is, although it sounds like $2500 may be around the limit? I have been subscribed to CanonPriceWatch.com for a few years now. I have a number of alerts set up in their system. Over the last couple of months, I've been getting a LOT of alerts about Canon's Mark II telephoto lenses. Several times over the last week and a half, I've been alerted of USED Canon EF 300mm f/2.8 L II lenses clocking in at ~$2700-2800. Given the list price for that lens, that is a superbly good deal!

For your motorsports and airshows, I really don't think you could do better than a 300mm f/2.8 II. It's eminently hand-holdable, the big aperture is ideal for the kind of fast moving subjects you shoot, and it easily adapts to 420mm f/4 with the 1.4x TC, which is still well within the realm of usability. If you really need it, you can always slap on the 2x TC for 600mm f/5.6 performance. I rented this lens a couple times a year and two years ago. I used it with both teleconverters. IQ with both was EXCELLENT. Even with the 2x TC, it performed as well or better than my 100-400mm lens, and the boke was always superior, regardless.

For $2700, even though that might be a bit beyond your desired budget, I really don't think there is a better lens for the kind of subjects you photograph. These deals come an go, and I've seen the lens sell used for as low as $2399. I'd go to CanonPriceWatch, find that lens, and set up some alerts for the used price range you would find acceptable (I'd say $2300-$2900 is very good for used), and take advantage of the next deal. New, this lens costs about $7300, and new deals rarely go below about $5500. I myself will probably be picking up a used copy, so long as it was well cared for, next time a $2700 deal rolls around. It's just too cheap to pass up.

I quite like motion blur, just so long as its only the background that is blurry. I need more practice panning to work on getting the shutter speed slower I think.

I think $2000 is the most I could go to. CanonPriceWatch looks very good, but it only covers Canada/USA I think? I brief google didn't reveal a UK based one. We have camerapricebuster, but it only covers new which is far beyond what I could afford. Like the idea of a 300 2.8, just out of my price range/needs for now though I think.

The only two options I'd consider (other than the Tamron 150-600 you tried and eliminated) are the 100-400L and the 2xIII (and the latter only because you indicate the 70-200/2.8L IS II in your sig, IQ takes a big hit with any other 70-200). FWIW, I have the 100-400, 70-200 II, and both MkIII TCs.

Between those two, the IQ is equivalent (lab tests give a very slight edge to the 100-400 at 400mm, but it's not a big enough difference to affect real world shots). The AF performance is similar, too (the 70-200 + 2x focuses slower and hunts more than the bare lens, putting it on par with the older, slower lens). IMO, the 100-400L handles better - shorter (when retracted), better balanced, no TC to mount. The 70-200+2x is cheaper, and gives you the option of a shorter f/2.8 zoom when the light gets dim without having to carry two white zooms.

Personally, if I'm going out to shoot mostly at 400mm, I take the 100-400. If I'm going out for more general shooting and want an opportunistic 400mm, I take the 70-200 and throw in the 2xIII.

I totally agree here with neuro.
And for the choice of the OP I would recommend the 2x TC to dhr90, because it gives you a more flexible setup and saves you some money compared to the 100-400.
The only other choice IMHO as you felt uncomfortable with the Tamron 150 - 600 would be the 100-400, and only if you

• like the push/pull
• know that you are more often in the 200 to 400mm reach
• don’t like the handling of the 70-200 with 2x TC on

I personally love my 100-400. But taking two whites with me would be too heavy and too much volume for me.
Have fun while choosing

I'm swaying towards the converter I think. I've no idea if I would like the push/pull design, I suspect I'd get used to it quickly enough, but the weight from having two whites with me would put me off a bit I think. When at racetracks I like to move around a lot and watch from lots of places so I would find the weight annoying after a while.

Just a thought, but would a 1.4x and a bit of cropping perform at least as well as a 2x? Image quality wise. Its only just occurred to me to consider this route. Slightly lighter, one less drop in stop and would give me just enough reach combined with some cropping.

I'm in no hurry to buy so taking time to try out all options is fine.

 

[Maximilian]

Just a thought, but would a 1.4x and a bit of cropping perform at least as well as a 2x? Image quality wise. Its only just occurred to me to consider this route. Slightly lighter, one less drop in stop and would give me just enough reach combined with some cropping.

I'm in no hurry to buy so taking time to try out all options is fine.

I have no "optical" experience with the 2x TC. I have the 1.4x and feel quite well with it. Therefore someone else has to tell you about how good cropping works in this comparison.
OTOH your arguments are speaking for themselves and only you can decide, if you need/want that 300 to 400mm reach optically. (I do)
One thing to mention comparing the 1.4x to 2x TC is the different balance point as the 2x TC is obviously longer. I didn't like that combined with a 70-200 2.8. But I already have the 100-400.
And as you have already tried that out, you are aware of that.
Still a difficult and interesting choice. Sorry for just showing arguments and not pointing clearly into one direction.

 

[Valvebounce]

Hi dhr90.
Personally I had been fairly happy with my 150-500 on my 40D, since I have been pairing it with my 7D I have been rather dissapointed, I have yet to work out if this is operator error, a greater mismatch of AF recruiting AFMA which I have yet to complete, see other posts by me about this!

Cheers Graham.

 

[kaihp]

Struggling to work out where was best for this topic. I know its been covered numerous times before, but I'm after more reach than 200mm of my 70-200 on my 7D. It would be used primarily for motorsports, airshows and wildlife

A couple of years ago, I faced the same issue: I found that my 70-200mm on my 50D didn't have enough reach for shooting motorcycles on racetracks, and I was looking to get (significantly) closer.

After trying a 400mm and a 300mm in a shop and some "thinking", I decided that 300mm wouldn't be enough and splurged on a used 400mm/2.8L Mk I. Only to find out that a 400mm on a APS-C got me too close to the action to be useful for me. I had to practice quite a bit to learn how to properly use the 400mm.

So my advice to you would be to check out if a 1.4x TC or a 300mm might suffice for what you want to do, or you really need the 400+mm.

Now that I have a 5D3, I'm looking forward to try the 400mm again to see if it has become more "user-friendly" for me.

 

[Don Haines]

Hi dhr90.
Personally I had been fairly happy with my 150-500 on my 40D, since I have been pairing it with my 7D I have been rather dissapointed, I have yet to work out if this is operator error, a greater mismatch of AF recruiting AFMA which I have yet to complete, see other posts by me about this!

Cheers Graham.

The Sigma 150-500 (and the 120-400) are very soft lenses. You really notice this when you go from a FF camera (big pixels) to a crop camera (tiny pixels). The 40D has a pixel size close to a FF camera and when you go to a 7D you are now using pixels that are half as large. This has the effect of making the lens even softer.

 

[jrista]

Just a thought, but would a 1.4x and a bit of cropping perform at least as well as a 2x? Image quality wise. Its only just occurred to me to consider this route. Slightly lighter, one less drop in stop and would give me just enough reach combined with some cropping.

I've used both TCs on the 300mm f/2.8 L II. In the case of that lens, specifically, the 2x produced better quality than with the 1.4x TC, and it produced better quality than the 100-400mm lens without any teleconverters at all with the exception of in the deep corners. I pretty much always crop just a little, even if it's only because of rotation, so the deep corner CA didn't matter to me.

Now, that is primarily thanks to the fact that the 300mm f/2.8 L II starts out as the sharpest lens in Canon's offerings. In the case of the 70-200 f/2.8 L II, the 2x TC will increase aberrations, however the effect is not uniform over the area of the lens. The corners may be worse than the 70-200/2.8 + 1.4x TC, but the center and some of the midframe are likely to be better. It really depends on what you need. In your case, I still think aperture is more important (unless your stopping down anyway for DOF), so you might indeed find that using the 70-200/2.8+1.4x with cropping and upscaling is still the better option. But if you primarily use the center area of your frame, the increased aberrations that occur when using the 2x TC will be minimal, and the added resolving power (added magnification) will still be useful.

To head off someone else sharing this, and claiming that the 70-200+1.4x is better than with the 2x. Here is an example of IQ with these two combinations using the ISO12233 chart:

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=687&Camera=453&Sample=0&FLI=6&API=1&LensComp=687&CameraComp=453&SampleComp=0&FLIComp=7&APIComp=2

The difference looks large and visibly measurable, however, in a real-world reach-limited scenario, the differences are FAR less. The problem with these kinds of charts is that the camera+lens is set up at different distances, such that the chart's cropping marks fill the frame in every case. That means the 70-200+1.4x (280mm f/4) combo is much closer than the 70-200mm+2x (400mm f/5.6) combo. That is not measuring the differences in a reach-limited situation. The 280mm combo is a little sharper in the test above, however if you downsample then upsample that combo by the proper ratio, you get the following:

This GIF was created by scaling back the 70-200mm w/ 1.4x TC samples by 1.42x on each edge, then upsampling it again, and layering those versions on top of the 70-200mm w/ 2x TC samples. You'll notice that in the center, the 400/5.6 combo is much sharper. Midframe there is no discernible difference. In the corners there is more CA in the 400/5.6 combo than the 280/4 combo, however the sharpness is roughly the same.

Assuming you place your subject within the center and midframe of the lens, your going to be losing more than you gain by upsampling images taken with the 280mm combo. The 2x TC, in reach limited circumstances, will always resolve more detail.

 

[Valvebounce]

Hi Jrista.
Thanks for the work you put in to that, that helps me to answer the same dilemma, Yey I got the 70-200 f2.8 for my birthday, and was wondering about the 1.4x 2x dilemma. I guess I know what I'm saving for, much cheaper than among for a longer white.
I think I may be hooked on white now, only had a chance to snap a couple of birds outside the hotel, no pc to load them on and look at them large, but wow really impressed so far.

Cheers Graham.