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Author Topic: Why no fixed Super-Tele-Lenses for APS-C?  (Read 4980 times)

unfocused

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Re: Why no fixed Super-Tele-Lenses for APS-C?
« Reply #15 on: December 19, 2011, 10:48:04 AM »
Quote
These birders all envy magnification and IQ of 300/2.8 or 500/4.0 but not only are unwilling to pay this kind of money - more importantly these lens-designs are to heavy for them to take them into the field.

I'm finding this whole thread a little confusing.

As a non-technical person, it once seemed logical to me that telephoto EF-S lenses could be made longer and lighter, but after reading many discussions of this on this forum (other threads) I gather that is not the case.

So, I'm wondering what is the point here?

Yes, physics is a real pain in the rear. But, it seems pretty clear to me that regardless of brand, once you get beyond 400mm or below f 5.6 the price skyrockets. I'm guessing that it might be possible to produce a 500mm f5.6 that's close to affordable and it would be nice if that were to happen. But, that's probably pushing the limit of what could be available with today's technology and manufacturing processes.

If it were practical to produce the lenses you suggest and make them affordable, someone would most likely be doing that. But, even Sigma's lenses get real pricey at the long end. The most "affordable" option is the "bigma" but it's more than the Canon 100-400 "L" and isn't nearly the lens. Their 500mm f4.5 is $5,000 and the prices go up from there.

Semi-superfluous comment No. 1: I think you're selingl the 100-400 "L" short. I think it's a better lens than you give it credit for being.

Semi-superfluous comment No. 2: Anyone with more knowledge care to comment on catadioptric (mirror) lenses. Both Canon and Nikon abandoned the lenses. While the the fixed aperture and donut-shaped bokeh aren't ideal, I don't think of them as deal-killers. Do they have sharpness issues and are these insurmountable?
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Re: Why no fixed Super-Tele-Lenses for APS-C?
« Reply #15 on: December 19, 2011, 10:48:04 AM »

7enderbender

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Re: Why no fixed Super-Tele-Lenses for APS-C?
« Reply #16 on: December 19, 2011, 10:53:58 AM »
I don't think this would be viable. As it is I doubt that Canon makes a lot of money from these specialty lenses and I'm pretty certain they maintain a full range of all sorts of gear mainly for marketing reasons. So adding even more specialized stuff that is expensive to develop and manufacture to cater to a small fraction of enthusiasts wouldn't make sense. I don't see how EF-S specialty primes would be any cheaper than what's already available in the EF line. Unless, of course, 35 mm sensor were bound to go away for the pro series. Doesn't look like it.

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whatta

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Re: Why no fixed Super-Tele-Lenses for APS-C?
« Reply #17 on: December 19, 2011, 11:15:58 AM »
Consider your suggestions in terms of the iris diaphragm (physical aperture, i.e. focal length / max f-number) size required:

EF-S 280/5.6 L IS USM - 50mm
EF-S 250/2.8 L IS USM - 89mm
EF-S 500/5.6 L IS USM - 89mm

The elements in front of the diaphragm must be large enough to fill it with light and avoid significant vignetting, i.e. a bit larger than the diaphragm itself.
sorry, I did not get it. what does it mean for
30/1.4 ? (filter 52mm)
60/2.8 ? (filter 62mm)

it gives 21mm, why do they have two-three times bigger filter? well, ok, 52mm is the smallest, but why 62mm then?
how do you count for FF?

Thanks a lot
« Last Edit: December 19, 2011, 11:21:15 AM by whatta »
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Mt Spokane Photography

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Re: Why no fixed Super-Tele-Lenses for APS-C?
« Reply #18 on: December 19, 2011, 11:56:41 AM »
Now that a 1Dx cannot AF at F/8, a 500mm f/5.6 L might make more sense.  We used to be able to use a 400mm f/5.6 and a 1.4X TC on our 1D series bodies.  However, $4k would certainly kill it, since you can buy a used 500 f/4 IS in that price range.

Cetalis

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Re: Why no fixed Super-Tele-Lenses for APS-C?
« Reply #19 on: December 19, 2011, 12:11:21 PM »
Likewise, I doubt we'd see a 300/5.6L, because there's already a 300/4L that's relatively inexpensive.

Perhaps there'd be room for an IS'd non L version? Or would that hurt 55-250 sales?

torger

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Re: Why no fixed Super-Tele-Lenses for APS-C?
« Reply #20 on: December 19, 2011, 12:25:13 PM »
sorry, I did not get it. what does it mean for
30/1.4 ? (filter 52mm)
60/2.8 ? (filter 62mm)

it gives 21mm, why do they have two-three times bigger filter? well, ok, 52mm is the smallest, but why 62mm then?
how do you count for FF?

Thanks a lot

I guess you wonder why 30/1.4 is not smaller in diameter than it is, since tele lenses are quite close max aperture and lens diameter. I'm no optics expert but I think it is because with wider angle lenses you need to take in light from a wider angle to get to the aperture which is sitting a bit back in the lens barrell. Also, there is a design tradeoff too, if let it vignette some more at largest aperture you can have smaller front element, so actually the wider angle lenses would typically vignette less if they had a larger front element.

neuroanatomist

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Re: Why no fixed Super-Tele-Lenses for APS-C?
« Reply #21 on: December 19, 2011, 12:54:16 PM »
sorry, I did not get it. what does it mean for
30/1.4 ? (filter 52mm)
60/2.8 ? (filter 62mm)

it gives 21mm, why do they have two-three times bigger filter? well, ok, 52mm is the smallest, but why 62mm then?
how do you count for FF?

Thanks a lot

I guess you wonder why 30/1.4 is not smaller in diameter than it is, since tele lenses are quite close max aperture and lens diameter. I'm no optics expert but I think it is because with wider angle lenses you need to take in light from a wider angle to get to the aperture which is sitting a bit back in the lens barrell. Also, there is a design tradeoff too, if let it vignette some more at largest aperture you can have smaller front element, so actually the wider angle lenses would typically vignette less if they had a larger front element.

Exactly - the numbers I was listing were for telephoto designs.  Normal and wide angle designs are different, with different requirements.  So are macro lenses - consider the MP-E 65mm, which uses a 58mm filter thread but has a relatively tiny front element.

Check out the article on lens geneaology for an interesting read...
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Re: Why no fixed Super-Tele-Lenses for APS-C?
« Reply #21 on: December 19, 2011, 12:54:16 PM »

Halfrack

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Re: Why no fixed Super-Tele-Lenses for APS-C?
« Reply #22 on: December 19, 2011, 02:59:35 PM »
Doing a Super-Tele for a crop body wouldn't make things easier, rather it would confuse more people than those it helps with a price point.  I would like to see a return of F2.8 NON-IS super-tele lenses since I shoot at a high speed - and this may cover part of that market.  The other would be a 300/4 that's setup with the built-in 1.4x tele-adapter.    Too bad people would see it and say 'well I already have half of it'...
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whatta

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Re: Why no fixed Super-Tele-Lenses for APS-C?
« Reply #23 on: December 20, 2011, 04:27:13 AM »
sorry, I did not get it. what does it mean for
30/1.4 ? (filter 52mm)
60/2.8 ? (filter 62mm)

it gives 21mm, why do they have two-three times bigger filter? well, ok, 52mm is the smallest, but why 62mm then?
how do you count for FF?

Thanks a lot

I guess you wonder why 30/1.4 is not smaller in diameter than it is, since tele lenses are quite close max aperture and lens diameter. I'm no optics expert but I think it is because with wider angle lenses you need to take in light from a wider angle to get to the aperture which is sitting a bit back in the lens barrell. Also, there is a design tradeoff too, if let it vignette some more at largest aperture you can have smaller front element, so actually the wider angle lenses would typically vignette less if they had a larger front element.
Exactly - the numbers I was listing were for telephoto designs.  Normal and wide angle designs are different, with different requirements.  So are macro lenses - consider the MP-E 65mm, which uses a 58mm filter thread but has a relatively tiny front element.

Check out the article on lens geneaology for an interesting read...
I will read it, thanks for you both.
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Re: Why no fixed Super-Tele-Lenses for APS-C?
« Reply #23 on: December 20, 2011, 04:27:13 AM »