35-70 f1

I have to say that I missed my optics Phd, but making some calculation about what I know about f-stops (the ratio between focal lenght and aperture), it seems to me that a 35-70 f1 should be possible to make.

As the 300 f2,8 show that an aperture of 300/2,8 = 107mm is possible, and also the magical 35-100 f2, wich I understand is a longer lens with a demultipler to enlarge the f-stops and bring back the lenght, show that the Zuiko guys can perform amazing things;

A 35-70 f1, with a 35mm equivalent of 70-140 f1 with the dof of a f2 (so perfectly usable, and not like the canon 50mm f0,85 with was a nightmare to use), will be truly the perfect portrait lens.
I will get that lens no matter the price, and I think many others will do it.

But as I says, I really don't know if this is possible to make, maybe that lens would require so small distance between the glass and the sensor that the mirror will go in the way? But shouldn't a demultipler take care of that?
Please discuss

-If memory serves me right, the Canon lens was an 0.95 as I sold many of them on the Canon 7 during the 60's

Jerry

Azhad said:

I have to say that I missed my optics Phd, but making some calculation about what I know about f-stops (the ratio between focal lenght and aperture), it seems to me that a 35-70 f1 should be possible to make.

Click to expand...

Probably possible: for example, Canon made a constant f/1.2 5x wide to telephoto zoom lens for 8mm movie film format.

But the aberrations and resolution might be unacceptable for a digital SLR. Movies need far less resolution --- especially the 8mm home movies for which that Canon lens was designed! It seems that the Olympus 35-100/2 and 14-35/2 are already difficult designs to get good resolution, and Canon, Nikon etc. have not even gone as far as 35-70/2.

At some point in the quest for speed, increasing sensor size and focal length at the same aperture ratio is probably better than pushing lens designs to ever lower aperture ratios and struggling with control of aberrations. My guess as to the limits for DLSR lenses able to handle 10MP and up: about f/2 to f2.8 for zooms, f/1.2 to f/2 with primes.

(Even with primes, Canon backed off from the f/1 of its former 50/1L to a f/1.2 replacement.)

One significant reason for making the sub-full frame cameras should be to allow smaller and lighter optics. Canon and Olympus have actually increased the size and weight of their "little" zooms compared to those from 35mm film days. Only Pentax seems to care.
Despite all the BS and hype about IS, it's not the same.

Shame (and a pox) on all of them!

It was a .095 If you focused on the nose the lips were out of focus at about 5'

Canon have had a couple of SLRs where the mirror remained stationary. Olympus did the same thing with the E10- E20.

No worry about the back of the lenses being to close and oh so quiet. Great design.

Glenn Smith

You miss 100% of the shots you don't take... ~ Wayne Gretzky

The larger the aperture, the wider the glass in front of the image plane. That implies bending the light at severe angles unless you move the front element(s) further away from the image plane. That in turn means bigger and heavier lenses, even more so than the aperture implies. Or, the f/1 aperture means truly exotic glass formulae, new levels of aspherics, and maybe even some magic tricks, such as the Canon DO elements.

If Olympus were to pull an acceptable 35-70mm f/1 zoom out of its magic hat, I imagine it to be truly massive and sporting a princely price.

http://www.dpreview.com/news/0610/06100101zeiss1700f4.asp

This fast lens was rumored to be many millions of dollars, possibly tens of millions.

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Cheers,

Jim Pilcher
Colorado, USA

'Begin each day as if it were on purpose.' -- Mary Anne Radmacher

I'm trying to recall the fastest SLR primes I've seen, and all I come up with is f/1.2. All fabulously expensive, big and heavy. As to the fastest (still photography) zooms I've ever seen...?

Would anybody buy a seven-thousand dollar four thirds lens that's not a fast super-tele?

--Rick

Yes you COULD make a 35-70/1 but really why would you? To make it any good it would have to have nothing but Super ED elements ground with the same precision they ground the Hubble's mirror with (and not including that idiotic calculating error they did to turn it into the Magoo scope for a few years) which would mean it would be 100k at least.

Then you have to figure the weight. I would weigh a ton and be tripod only which would defeat its whole purpose.

I mean just look at the Leica Noctilux. It's over 2x as large as their 50/2.0 Summicron. Dunno what the performance of the two is but I'd bet the 50/2.0 is better at 2.0 than the Noctilux.

When you could make a catadioptic lens that would be hundreds of pounds lighter and millions of dollars cheaper.

Skeeterbytes said:

Would anybody buy a seven-thousand dollar four thirds lens that's not
a fast super-tele?

--Rick

Click to expand...

Just look at the noctilux, yeah its a leica, but still 4000€ and more, and that is just on ebay.
I really hoped too much, but at least a 35-70 f1.4 would be great.

Olympus don't seem to like primes much this days, so I can't wish for a 50 f1, but maybe a zoom would appeal to them more

And big? I don't think that would be much bigger than the 35-100 f2 (prefectly hand-holdable) or maybe the 150 f2 wich have an aperture of 75mm opposed to the "only" 70mm the 35-70 f1 would require.

lloyd007 said:

When you could make a catadioptic lens that would be hundreds of
pounds lighter and millions of dollars cheaper.

Click to expand...

...is that the person who commissioned the lens is a fabulously wealthy arab dignitary from Qatar.

Mirror lenses have those awful donut-shaped OOF highlights. They are merely curiosities to serious wildlife shooters, which the purchaser claims to be. Also, a 1700mm f/4 mirror lens might be as much as a meter across!

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Cheers,

Jim Pilcher
Colorado, USA

'Begin each day as if it were on purpose.' -- Mary Anne Radmacher

You purchase the Noctilux for its f/1 aperture, not for it ultimate sharpness. It is not seriously sharp at f/1 or f/1.4. Neither was the Canon EF 50mm f/1 L.

You buy fast lenses in order to use them wide open. Good performance at smaller apertures is a bonus.

--
Cheers,

Jim Pilcher
Colorado, USA

'Begin each day as if it were on purpose.' -- Mary Anne Radmacher