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Author Topic: Plausibility of a 100-400mm f/4 L IS USM?  (Read 5983 times)

lol

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Re: Plausibility of a 100-400mm f/4 L IS USM?
« Reply #15 on: February 19, 2012, 06:16:30 AM »
If we're going down to this level of nit picking, let me clarify what I said. Observing from infinity, the apparent size of the entrance pupil will tend towards that of the lens front opening for longer focal length lenses. That is the measure that is of practical significance, regardless where or how big the actual physical stop is. I think we were saying the same thing but from totally different directions.

And I think most people would say the difference of 1 stop is significant enough. Approx. 1.4x linear, 2x in area and possibly more in volume terms since individual lenses elements aren't paper thin. For the same focal length and a comparable quality of design, there's no escaping the increase in glass required as aperture increases.

Side note: Bigma commonly refers to the 50-500. I'm guessing the earlier reference was more towards the 200-500/2.8 which certainly is a monster! You can hand hold that...

But on that note, and not something Canon would ever do... there is the third party trick of making the lenses f/6.3 on the long end which would give a small saving on size, weight and cost. Not a huge amount for sure, but when you're getting to longer focal lengths it could help a bit.

Personally I'm debating between the new 200-400 and the Sigma 120-300 with a 2x strapped on it. I'm pretty much waiting confirmation the 200-400 will cost more than my car before I get the Sigma!

And on one final thought, if anyone is still reading at this point. Would you buy a lens that was intentionally under-designed if it made a significant reduction to the cost? I know we all want the latest L lens, not so much the price that goes with it. But look at the lessons from the mirrorless cameras. Allow the easier to fix flaws of a lens to remain to help make them smaller and cheaper. Lateral CA and distortion are both easy to correct in post processing. If you allow them to remain in the lens design, how much simpler could the lens be? Maybe require less exotic elements too.
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jrista

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Re: Plausibility of a 100-400mm f/4 L IS USM?
« Reply #16 on: February 19, 2012, 03:52:36 PM »
If we're going down to this level of nit picking, let me clarify what I said. Observing from infinity, the apparent size of the entrance pupil will tend towards that of the lens front opening for longer focal length lenses. That is the measure that is of practical significance, regardless where or how big the actual physical stop is. I think we were saying the same thing but from totally different directions.

And I think most people would say the difference of 1 stop is significant enough. Approx. 1.4x linear, 2x in area and possibly more in volume terms since individual lenses elements aren't paper thin. For the same focal length and a comparable quality of design, there's no escaping the increase in glass required as aperture increases.

True, comparing my 100-400 vs. my 16-35, I see what you mean by entrance pupil size (that telephotos tend towards the size of the front element, where as wide angles don't even come close.)

Side note: Bigma commonly refers to the 50-500. I'm guessing the earlier reference was more towards the 200-500/2.8 which certainly is a monster! You can hand hold that...

Sorry, it is the 200-500/2.8 that I was referring to. I've seen that picture before...its hilarious, and not something I would venture to do myself. I'd slap that puppy onto one of Gitzo's 5000 series uberpods with a gimbal.

But on that note, and not something Canon would ever do... there is the third party trick of making the lenses f/6.3 on the long end which would give a small saving on size, weight and cost. Not a huge amount for sure, but when you're getting to longer focal lengths it could help a bit.

I'd be willing to go for an f/6.3 aperture so long as it still autofocused. I'm never sure what the limit is on non-1D bodies: AF for less than f/8, or AF up to f/5.6? A third of a stop won't affect DOF that much, and I often shoot f/7.1 or f/8 anyway.

Personally I'm debating between the new 200-400 and the Sigma 120-300 with a 2x strapped on it. I'm pretty much waiting confirmation the 200-400 will cost more than my car before I get the Sigma!

I'll have to take a look at the Sigma. I know Canon embeds a lot of AF related functionality into the microprocessors of their lenses, as well as their teleconverters. I've always worried that if I used a non-Canon lens that AF would not work as well or as efficiently. Particularly with one of their TC III's.

And on one final thought, if anyone is still reading at this point. Would you buy a lens that was intentionally under-designed if it made a significant reduction to the cost? I know we all want the latest L lens, not so much the price that goes with it. But look at the lessons from the mirrorless cameras. Allow the easier to fix flaws of a lens to remain to help make them smaller and cheaper. Lateral CA and distortion are both easy to correct in post processing. If you allow them to remain in the lens design, how much simpler could the lens be? Maybe require less exotic elements too.

You can correct both in post processing, however only to a degree without affecting IQ. Most CA corrections fix the discoloration and try to rebalance tone, but the IQ impact is always there, to one degree or another. Correcting distortion in post requires shifting parts of the image, which causes interpolation (sometimes a lot, depending on how bad the distortion is). So, if those kinds of things don't matter, then sure, you could probably get away with buying much cheaper uncorrected lenses. If they do matter, then your just kind of stuck... :\
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Caps18

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Re: Plausibility of a 100-400mm f/4 L IS USM?
« Reply #17 on: February 19, 2012, 04:47:22 PM »
If only I had won the lottery...

The 200-400 f/4 looks nice.  I would have liked it to have the tripod ring collar that my 300 f/4 has...

If they mad the 300 f/4 with a built in 1.4x extender, that would be nice.  I'm not sure if they could make one that is f/4 at both focal lengths though.
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DavidRiesenberg

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Re: Plausibility of a 100-400mm f/4 L IS USM?
« Reply #18 on: February 19, 2012, 06:13:25 PM »
Taking into consideration Canon's latest lens pricing policies, I find it hard to believe the 200-400 TC will cost less than 10K. And it wouldn't surprise me if they'll also release sometime in the future a version without the TC but that will also be very expensive. Probably in the 7K region.

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Re: Plausibility of a 100-400mm f/4 L IS USM?
« Reply #19 on: February 20, 2012, 07:44:05 AM »
You can correct both in post processing, however only to a degree without affecting IQ. Most CA corrections fix the discoloration and try to rebalance tone, but the IQ impact is always there, to one degree or another. Correcting distortion in post requires shifting parts of the image, which causes interpolation (sometimes a lot, depending on how bad the distortion is). So, if those kinds of things don't matter, then sure, you could probably get away with buying much cheaper uncorrected lenses. If they do matter, then your just kind of stuck... :\
With lateral CAs, it can be dealt with relatively easily by scaling the colour channels appropriately. Yes, this and any distortion correction will cost resolution. But the point is, how much cheaper could a lens be if they did this? It might or might not be significant. Put it this way, say you had two choices:
1: best ever, very expensive
2: good enough, affordable
If you can't afford 1, wouldn't you be looking at #2?
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KeithR

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Re: Plausibility of a 100-400mm f/4 L IS USM?
« Reply #20 on: February 20, 2012, 08:38:27 AM »
I'll have to take a look at the Sigma. I know Canon embeds a lot of AF related functionality into the microprocessors of their lenses, as well as their teleconverters. I've always worried that if I used a non-Canon lens that AF would not work as well or as efficiently.
On that...

I read a review from a few years back of the Siggy 300mm f/2.8 prime, where the reviewer - a knowledgeable and experienced bird guy - stated quite unequivocally that (attached to a Canon body - an old pro film body, but that might not matter) with the Siggy 2x attached, AF was pretty much as quick as the bare lens.

Quote
However, upon depressing the shutter button to activate autofocus, I immediately noticed the first real difference; unlike the Canon combination, the Sigma 300/2.8 appears to focus as swiftly and surely with the converters as it does without them! This has always been a trait of the Canon lens/teleconverter combination that annoys me; as soon as I install the matched Canon 1.4X teleconverter on my EF 300/4L lens, autofocusing becomes noticeably slower. Even with a 2x teleconverter in place, yielding a 600mm f/5.6 super-telephoto, the Sigma's autofocus performance remains superb.
On that basis I picked up a used Sigma 2x myself last weekend (the older non EX model - it was cheap enough at £109 that if things didn't go as well as planned I'd be able to offload it again with little or no loss) and tested it out yesterday with my 120-300mm f/2.8 OS and 7D.

While I can't say for sure that it was as fast as the bare lens to AF, it was definitely as fast as the Siggy 1.4x I've got (which is - I think - a teeny bit faster than my Canon Mk II 1.4x), and with little or no observable IQ hit: in fact sometimes the 2x seemed to be sharper than the 1.4x, but because I shoot handheld and was in and out of all sorts of changeable light I'm not reading too much into that.

Suffice to say though, the Siggy and Siggy TCs work very well together - I'm really pleased by my experiences so far: and for the avoidance of any doubt, I am obsessively fussy about IQ.

Even so, my next step will be to bung my Kenko non-reporting 1.5x in between the body and 2x, and see how usable 900mm is!

;)

« Last Edit: February 20, 2012, 08:48:30 AM by KeithR »

AprilForever

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Re: Plausibility of a 100-400mm f/4 L IS USM?
« Reply #21 on: February 20, 2012, 10:08:39 AM »
I'm a big fan of my 100-400mm f/4.5-5.6 L IS USM lens. Its served me quite well, and better than the 400mm f/5.6 lenses I've tried from friends or other fellow photographers met out in the field. The only real detractor, however, is the aperture range...f/4.5 to f/5.6 is a bit limiting, from an AF standpoint, and from the standpoint of using a teleconverter. I'd love to have a relatively affordable telephoto zoom lens that I could slap a 1.4x TC on to get 140-560mm f/5.6, something cheaper than the new 200-400mm f/4 L IS USM.

Is a 100-400m f/4 a plausibility, for a "reasonable" cost around $3500 or so? Would it be a lens anyone else even cared about, or is that just a focal range and price that doesn't serve anyone's needs? Personally, I'd find 560/5.6 to be far more useful for general bird photography, without having to lug around a heavy 500mm or 600m L.

Thoughts?

Even a bare 400 f4 prime would bite you for much more than 3500. The 200 f2 goes for around 5000. The 300 2.8 mkI went for around 5000. So... It would probably go for over 5000...
What is truth?