Why no cheap f/1.0 fixed lenses?

If it were fixed at infinity it would be useful for astronomy type applications possibly.

OK, it'd be of limited use.

I thought about having it focused at the hyperfocal distance though? Low-light landscapes?

Canon has made a 50mm f1.0 lens.
http://www.wlcastleman​.com/equip/reviews/50m​m/index.htm
Very difficult to make a lens this fast without other compromises though.

There's nothing cheap about making a lens that bright... And still have usable images.

motoroller wrote in post #7802018
They could make a telephoto one which has handhold speeds in any light for birding / sports...

a 300mm f1.0 would need a front element of greater than 300mm in diameter, because the iris opening would need to be 300mm.

a 400mm f1.0 would need a front element of greater than 400mm in diameter, because the iris opening would need to be 400mm.

such lenses would weight in excess of 15 lbs. Frankly, they may offer handholdable "speeds" but you'd need to be a body builder to hand-hold them. Plus, the cost of such glass fabrication would be astronomical. To put it into perspective, a 400mm diameter glass element is about 16" wide. Thats huge. No one WANTS that, it would be like carrying a large gaussian telescope around.

laydros wrote in post #7802079
Good point, the DOF of f/1.0 or even 1.2 is tough to control. Like I said, limited use = limited sales.

But people run to the next model camera because it has higher megapixels, so proper (and slightly deceptive) marketing can do wonders for sales of things that people don't need.

motoroller wrote in post #7805367
OK, it'd be of limited use.

I thought about having it focused at the hyperfocal distance though? Low-light landscapes?

The hyperfocal distance of a 75mm lens at f/1.0 would be very near to infinity anyway. Not very useful still.

Madweasel wrote in post #7802808
There's no need for a cheap lens to be fixed focus. A simple helicoid mechanism is all that's required to move the whole assembly in or out to focus.

I think there is a bit more than that to it. The R&D, the engineering would certainly cost a bunch. The elements need to shift in relation to each other as well as the entire group.And, I would think some expensive, custom glass would be needed.

jr_senator wrote in post #7807671
I think there is a bit more than that to it. The R&D, the engineering would certainly cost a bunch. The elements need to shift in relation to each other as well as the entire group.And, I would think some expensive, custom glass would be needed.

Definitely custom glass, but the simplest way of focussing is to move the whole assembly. Lots of lenses do this, including the 50mm f/1.8. Unless you mean that to maintain a good image close up the lenses would need to move relative to each other, then yes they would - I think the 35mm f/1.4L does that. Either way, we quickly move away from the OP's desire of a cheap, fast lens.

motoroller wrote in post #7802018
They could make a telephoto one which has handhold speeds in any light for birding / sports...

If you are talking about an F1.0 telephoto lens, it would be practically impossible!!!

If you're talking birding/sports, then you must be talking around 200mm at a minimum....

So in order to be F1.0, the effective aperture would need to be 200mm (e.g. F1.0 = 200mm/200mm, F4 = 200mm/50mm, etc). This would mean that the front lens element glass of such a lens would need to be about 200mm, or around 8" across!!!!! It would probably cost around $30,000-$50,000 !!!!!

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Oops, I just saw the similar post by nureality!!!

A fixed f/1 would be a nightmare lol. Maybe a fixed f/8 or f/22+

jr_senator wrote in post #7807671
I think there is a bit more than that to it. The R&D, the engineering would certainly cost a bunch. The elements need to shift in relation to each other as well as the entire group.And, I would think some expensive, custom glass would be needed.

There's no need to move the elements relative to each other. All of the lenses which don't have internal focus do this - the whole lens assembly shifts in and out.

So all you have to do is to mount the thing on bellows and one would be able to focus. If you were to make a lens which is about 1-1.5 meters away just for headshots, I'd get one.

What is custom glass? helicoids R&D have been completed about 500 years ago.

DocFrankenstein wrote in post #7809474
There's no need to move the elements relative to each other. All of the lenses which don't have internal focus do this - the whole lens assembly shifts in and out.

So all you have to do is to mount the thing on bellows and one would be able to focus. If you were to make a lens which is about 1-1.5 meters away just for headshots, I'd get one.

all you have to do is helicoids R&D have been completed about 500 years ago.

Doc, you want to rethink this? I have owned and used lenses where there is a shift of the rear elements only. I have no idea if this would be necessary for the lens in question, but to make the statement, " There's no need to move the elements relative to each other." is false.

Bellows? I haven't had a lens that required the use of a bellows in decades. "...all you have to do is to mount the thing on bellows"? Start a poll and find out just how many photographers are willing to use a bellows. Other than you I don't think anyone considers it "all you have to do" worth having the lens.

"all you have to do is helicoids"? Well, I don't know how you figured this out yet but maybe the engineers designing a new lens from the bottom up would disagree. After a little R & D that is. And special glass has been around 500 years? Just to name one, Sigma's 120-400mm lens uses both Special Low Dispersion glass (and they had this 500 years ago?) and a rear element focusing system, and it sure ain't the only lens that does.

I think the most important reason is simply the technical barrier. A 200mm f/1 lens would be HUUUUUUUUUUUUUUUGEE and really $$$$$$$$$$. Look at all of Canons quality large aperture lenses; they are pretty dam big, heavy, and expensive. None of which I like.

khall wrote in post #7802961
Canon did make a 50mm f0.95 lens and was sold late 50s and early 60s

Look at my avatar.

The Canon 7, which was a direct competitor of the Leica M3, and used a Leica mount. It was introduced in 1961.
There's less information around about the lens though, which is a 50mm f/0.95.

Either way...I want one.