What are the lenses you wish cabin would make?
- Thread starter Dpcj2
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I’d love RF-S versions of their 600/800mm F11s. Not a redesign, just the exact same optical formula modified for an aps-c image circle, so there’s no crop.
This wouldn’t require major changes, right? I feel like it’d be cheap to develop.
AND it would be the perfect companion for the R7 II launch. Birders would buy them like hotcakes.
This wouldn’t require major changes, right? I feel like it’d be cheap to develop.
AND it would be the perfect companion for the R7 II launch. Birders would buy them like hotcakes.
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As has been said many times on the forum, there are no APS-C-specific long lenses because they would not be smaller. I'll let Neuro or AlanF explain the optics if they have the patience. I don't even know what "the exact same optical formula" means with a different-sized image circle. Anyhow Canon offers a suite of small*, light*, cheap* supertelephoto options that work fine with crop bodies, you won't get anything better in the foreseeable future.
*always relative terms, but eg the 800 can be had for ~£800 which would have seemed fantastical in EF days.
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I know. I don't mind the physical size. I just want the crop removed and (presumably) an f-stop back.
As an example of what I'm referencing, EF telephotos can be adapted with 0.7X "speed booster," one final optical addition, that removes the crop and yields an extra stop of light.
Yes, I know the extra optics degrades quality, but that's not my point. I don't want an actual speedboster.
I want Canon to replace the "back few" lenses in the optical formula, so the image circle it projects is aps-c, but otherwise the length, size, everything is all exactly the same. To my understanding, there's no engineering problem with this, and now Canon has a good commercial reason to do it.
EDIT: To be clear, this would mean the 800mm F11 would now be sold as a ~500mm on the box. The 600mm f11 would now be ~375mm. But that's fine. On a crop sensor, that's still a TON of reach, and I think the extra light/sharpness would be worth it.
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At longer telephoto focal lengths (over 250-300mm), the size of the image circle is not a limiting factor in the design. So the lens would be the same size.
Look at the specs for the OM 150-400, same size as the EF 100-400L but the former is for a 2x crop sensor.
So you’re talking about 600mm and 800mm ‘equivalent’ lenses that are 1.3-stops faster. So the 800/11 becomes a 500/7.1 and the 600/11 becomes a 375mm f/7.1. So the lens you want exists, it’s the RF 100-500mm f/4.5-7.1.
If the cost is too high, get the RF 100-400mm f/5.6-8, it’s 1/3-stop slower and ‘only’ 640mm equivalent, but it’s close and a great value for the IQ.
Canon is not going to make a 500/7.1 or a 375/7.1 prime lens. Period.
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Yes exactly!
The RF 100-500mm is $2600, on sale.
I can't justify dropping $3000 on a lens. Heck, I can't do it, period.
But the 600mm/800mm F11s are well below $1K, and AFAIK considerably lighter.
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A 0.7x speedboster reduces focal length by 30% as it gives an extra stop of light. So, for example, if you put a 0.7x on a 600mm f/4 lens you end up with a 420mm f/2.8. It doesn’t remove the crop, it is just the same as putting a full frame 420mm f/2.8 on the crop camera.
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As I added with my edit, look at the RF 100-400 f/5.6-8. It’s a great lens.
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Indeed.
But 500mm is still significantly more reach, and while the 100-400 is not prohibitively expensive, it's still more expensive than street prices I'm seeing for the 800mm F11
I could get a teleconverter for RF 100-400. But I looked an an A/B tests of that vs the 600mm f11, and the 600 came out much sharper.
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Given the existence of the RF 100-500 and RF 100-400, do you believe Canon launching a 500/7.1 prime is in any way a possibility? Personally, I think we’ll see pigs flying over snowball fights in hell first.
You’re probably better off hoping for a 0.7x RF speedbooster to use with the 800/11.
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I dunno.
One one hand, it’s a long shot. Yeah…
On the other, seeing how much R7 users love the 600mm, I think wildlife shooters/birders who want to drop less than $3K on a lens, and have something lightweight, would eat it up. It’s longer and brighter than the 400mm. 800mm FF equivalent with that much brightness would perfect.
I know I you were joking, but RF (as far as I know) can’t have speed boosters. They only work for EF -> RF converters because of the extra space between the lens/body, and I don’t think I would want the sharpness hit from an adapter anyway.
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A 500mm APS-C would also be a 500mm FF lens as its image circle would be large enough to cover FF, which is what @neuroanatomist and I are trying to explain. It's only much shorter focal length lenses that have image circles that are too small to fit FF.
Tamron makes an RF-S 18-300. Guess it's RF for a couple of reasons. First, Canon won't allow them to market RF lenses. Secondly, the 200-300mm long end most certainly covers a FF sensor but the 18-50 probably doesn't.
If canon can make a sharp RF 800mm f/11 at a reasonable price, I am pretty sure they could do the same for an RF 400mm f/5.6 as the optics at the front would have the same diameter and it would be much shorter. They clearly don't want to undercut their expensive zooms.
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That’s not what I mean though. A crop sensor with a full frame circle is getting a cropped view.
Altering the design to be aps-c with the (approximately) same physical dimensions yields a smaller, brighter circle with less zoom for the same physical lens design. That’s the tradeoff. That turns an 800mm into a ~500mm, and a 400mm prime would physically resemble a reconfigured 600mm F11 afaik.
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That is the issue though, isn’t it? Even if Canon can do it cheaply, they won’t.
I think they want everyone to buy FF glass to incentivize upgrading to FF bodies. Which is exactly what R7 users ended up doing, I suppose.
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Sorry, but I don't think you're getting the point here. An 800mm lens design is going to have an image circle larger than a FF sensor and thus larger than an APS-C sensor. A 500mm lens is still going to have an image circle larger than a FF sensor and thus larger than an APS-C sensor. You cannot 'design a smaller, brighter image circle' for a supertelephoto lens. The image circle is not limiting for FF, so it's not going to be limiting for APS-C.
Ok, I get that what you're suggesting is that Canon effectively design an 800mm lens with a speedbooster built into it. But that design would yield 500mm f/7.1 and would still cover a FF image circle, so what would be the point? A simple 500/7.1 would be a lot cheaper to build than a speedboosted 800/11, and it would be lighter, too (less glass).
There are no long telephoto lenses for APS-C. None. Even if the above point about the image circle not being limiting is not clear to you, you should think about why no one has made one – if it made any sort of sense, an OEM or 3rd party lens maker would have done it. Even with brands that only make crop sensors, like Oly/OM, their lenses that go beyond 300mm would actually work on a FF sensor. Because the image circle is not limiting.
The issue is that there is simply no point in making the lenses you are talking about. Not just from a cost perspective, but from an optical physics perspective.
This is also true, of course. It's likely why there are few high-end APS-C lenses from Canon and none for the RF mount, and why there has never been an L-series APS-C lens (though they do put them on fixed-lens camera with smaller sensors, like the PowerShot Pro1 and several camcorders). But that is irrelevant in this case.
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If you alter the design of a telephoto lens to have a smaller brighter circle then it automatically decreases the focal length of the lens because it means you put in an element that focuses the light into a smaller area.
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