Here are the RF 600mm f/11 & RF 800mm f/11 super-telephoto lenses
- Thread starter Canon Rumors Guy
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The main reason those lenses stopped being made was for the same reason the 1200 stopped being made. Cost.
Was it cost? The 800mm is an f/5.6 and has a slightly smaller diameter front element than the 600mm f/4. I'd be surprised if there is much difference in cost of manufacture. A 600mm f/4 is just so much more versatile giving 600mm f/4, 840mm f/5.6 and 1200mm f/8, compared with 800mm f/5.6 and 1120mm f/8.
I've posted elsewhere here that on a 50 Mpx sensor dropping the aperture from from f/5.6 to f/11 loses about 15% in resolution because of diffraction.
Yep. I'm stunned. You were righter and I was wronger.Ok definitely the 600mm price was a bit delusional but I wasn’t far off on the 800mm price!
Don't disagree. I own the Sigma Contemporary and while I'd like something lighter, it's not worth the trade off in f/stop. It's hard enough to get enough light for f6.3, much less for f11.
We needed big apertures in the past for the following reasons:
- make the viewfinder bright enough to see and focus manually
- allow autofocus to work (was f/2.8 for most of the film era, maybe f/5.6 for center sensor only)
- allow hand-holdability (just about impossible with the 600/4, which I own)
- allow fast enough shutter to freeze action while maintaining a given level of grain/noise
- blur background.
So basically for giving up 4, you're getting a lens that might be 10x lighter, 30x smaller, and 10x cheaper.
I imagine they'll come out with extension tubes soon enough. I could use a 12mm tube on my 600/4 and still infinity focus, due I assume to tolerances in the system.
I like butterflies, so if I got one of these I'd totally get an extension tube for it.
They should still be able to do a great job giving blurred, smooth backgrounds.
That blur doesn't come from f-stop, it comes from aperture. Many people use the terms interchangeably but aperture is the "hole" you see in the front of the lens when you hold it up to look through it. It's also called the "entrance pupil." The blur area is proportional to the area of this aperture. The blur width, if you prefer to think in linear terms, is proportional to the width of the aperture.
The 600/11 will have a 54mm aperture. Even the 50mm f/1.0L lens only had a 50mm aperture, so this will blur even more than the 50/1.0 wide open.
The 800/11 will have a 72mm aperture, which is the square root of two bigger than the 50mm's 50mm aperture. That means the blur would be 1.4x the width, or 2.0x the area, as you'd see by cropping a 50/1.0L image after shooting both lenses wide open.
It might be rather a long extension to have a serious effect on the mfd of an 800mm lens. How much effect on mfd does the 12mm have on your 600mm?
Actually f/6.3 and f/11 are about 1.7 stops apart, f/9 would be one stop from f/6.3.
Modern sensors are very efficient at harvesting light and there is very little room for improvement, unfortunately.
I'm interested that the Canon Software claims to be able to correct even this diffraction to some extent but I can't figure out how. (As an engineer many things I can figure out but not this.)
Well, dynamic range can easily be doubled, and I'm actually thinking we'll probably move to an 8-primary system at some point, probably with Apple leading the way, in order to capture 98%+ of the visible color range... Though as far as noise, you're certainly right that there's little room for improvement. And yet, what little room there is doesn't mean that improvement's impossible.
It is probably a Form of deconvolution they are using, similarly to the SmartSharpen Filter in Photoshop? I haven't used the Canon one myself, so that's just a guess.
You have made this point a couple of times. But its wholly irrelevant. The subject distance used for a 600mm lens and 50mm lens are typically completely different and so is the focusing distance btw. So different F/-stops going from say 600mm f/5.6 to F/11 absolutely matters because it shows different degrees of blur - at a long distance.
This is why I and others are willing to pay a huge premium to have a 300mm and 400mm f/2.8 in stead of a 300mm f/4 or 400mm f/5.6 lens.
Neither can I Frank. I think for simple systems you can do Fourier analysis of the point spread function but I don't know how they do this for the digital images that we generate.
Addition - there are approaches that do this, the Lucy-Richardson Algorithm is one that is frequently used - see https://www.mathworks.com/help/imag...the-lucy-richardson-algorithm.html#d120e36224
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Of course. I NEVER qualified as: if the subject distance was the same.
I said, if the subject size was the same.
Wholly irrelevant? Not to people who take pictures. You seem to know nothing about the effect of aperture size (not f-stop) on background blur. Why don't you go spend some quality time with some big lenses until you figure this out, then come back and tell me what's wholly irrelevant. Get a 50/1.0 and shoot your 600/4 or whatever at the same 50mm aperture, (that's f/12; I sense I have to spoon-feed you these things), and the same subject size, and report back what you learn.
Wow, "you and others" wasted your money then. Even stopped down a fair amount you can get pretty blurry backgrounds. My above note on aperture is a mini-course on the subject and you could clearly use it. Meanwhile, the actual reasons most people buy the big lenses are explained in my other note above. You're welcome to scroll back and study it too.
If you have time between telling strangers that they're totally irrelevant, that is.
