Why is Aperture so limited?

[adauria]

I was discussing lens aperture with a non-photo geek friend the other day, and he asked if lens makers charge so much for lenses with wide aperture as a scam. I told him, no, that there must be some technical reason why lenses don't all go to F/1... but I don't know enough about how lenses are made / how they work to really understand this.

Anyone have any good knowledge on why you pay so much more for faster lenses?

Thanks!!

[grego]

I'm sure someone will have a good technical explanation, but more glass is a big reason.

[tim]

More glass, more precision required in manufacturing, and more design time to make it look good are three reasons.

[mebailey]

Cost, size, weight, and poor image quality and DOF at f1.

[Snapman]

I'm sure someone will have a good technical explanation, but more glass is a big reason.
I've no idea how lenses are made, so can you tell me whether it really takes a lot more work to grind a big lens accurately than a smaller one? Given the vast difference in price, I find it difficult to believe that it's just a matter of the extra amount of materials involved.

[ricohcam01]

Mr. 2 cents is here to bend your eye.

I think with all that was said so far we are forgetting supply and demand. Up until about 6 months a go I didn't really know the differance. Now if the general public knew the benefets of a 1. what ever lens then the prices would come down. It is the real die-hards that know the differance and the more people learn we will all benefit.

I have a Pentex 645 with a 75mm 2.8
I have a 28-80mm kit lens that starts at 3.5

No camera sales person ever told me the benefet. I had to find out myself!

[Keiffer]

Number 1 has to be DOF, I can only imagine the narrow depth of field, Shoot a face and everything from the eyes back are OOF LOL

[DavidEB]

Several things about manufacture: surface area goes up as the square of the f-ratio goes down, so the amount of glass to be polished increases. The lower f-number requires thicker glass to bend the light at a steeper angle at the edges, so the volume of glass goes up as the cube of the f-number goes down. So the probability of having an imperfection in the glass itself (bubbles, etc...) increases dramatically. The number of elements required to correct spherical and other abberations goes up. Finally, the precision of manufacturing, and particularly of the focusing mechanism, increases. There may be many other reasons also.

[daveh]

There is a Canon 50mm f/1.0L. It's about $3000 more than the f1.4, however, so you don't see very many. At one time they made a 50mm f/0.9 or maybe it was an f/0.95.

The big lenses do cost more to make but I've noticed that over the last 40 years or so, that the price range from high end lens to low end lens has widened. When I started out, all SLR lenses were serious amateur to professional and all cost a lot. As SLRs started to become the fashionable camera to have in the 70s, they introduced zoom lenses at much lower prices while the highest end lens prices went up. I think it's just standard market segmentation - ie: sell a bunch of pricey stuff to people who can and will pay for it (pros and a few well-off amateurs) and also sell a large quantity of not-so-profitable stuff to people who can't/wont.

Back in the 60s a mid-end Mercedes was priced lower than a large Ford too. Then currencies shifted in value and Mercedes was surprised to find that demand in the American market actually went up as their cars became more expensive.

[robertwgross]

There are different ways that a camera company looks at this.

One is cost-based pricing. For example, if the labor and component costs are $100, then they may charge $400 for the lens. If the labor and component costs are $200, then they may charge $800 for the lens.

One is value-based pricing. For example, if consumers pay $400 for a lens of a certain sharpness, then maybe they will pay $800 for a similar lens that is much sharper.

One is market-based pricing. For example, if Brand X charges $400 for a lens, and if Canon wants to take away market share, then maybe Canon charges only $350 for an equivalent lens.

However, from the point of practicality, there are very few f/1.0 lenses on the market, partly because of the huge weight of glass that is going to be involved. As a result of that and the manufacturing costs, that sucker is going to be very specialized and very expensive. As a result of that, there will be very, very few sold. As a result of that limited volume, the actual price is driven up higher and higher to the point where you won't find many at all for any price.

---Bob Gross---

[KevC]

f/stop is... the measurement of the relationship between focal length and aperture size (how big the hole is). So just ... for second... imagine f/1. It's exactly as wide as the focal length. I'm no engineer, but I can imagine how much it will cost to make it that big and still, as others have said, retain sharpness and colour/contrast.

I hear the 50mm f/1 isn't anywhere as sharp or contrasty as the 50mm f/1.4. Obviously it has way more light sucking ability...

[Andy_T]

When looking at production costs, don't just look at the manufacturing costs for a single lens. Look also at the design and test cost, the cost for hand-tooling the prototypes, for setting up the tools, programming the CNC machines, etc...
All that amounts to quite a nice sum.
If you can spread this sum over, say, 1,000,000 EF-S 18-55 kit lenses, it'll only be a few dollars per lens. If you spread it over 1,000 EF 1200/5.6 lenses, then the cost per lens will be considerable ... in addition to the manufacturing costs, that will also be considerable.

If you want to know more about the production process of Canon EF lenses, take a look at the Virtual Lens plant at the Canon camera museum. (http://www.canon.com/camera-museum/tech/l_plant/f_index.html)

Best regards,
Andy

[Jon]

OK - simple explanation. Broad, sweeping generalizations alert. Take a basic lens design, like the tried-and-true 50 f/1.8. It's a time-honored lens design using only 6 lens elements. Now to make it an f/1.0, you need to approximately double the diameter of each lens element. Which means you square the area. Which means you increase the volume on the order of the third power (thus the weight goes up, fast). So an f/1.0 lens using the same design as the 1.8 will be significantly larger and heavier. And have a lot more lens surfaces to be ground/polished.

That same basic design 1.0 won't be as good as a 1.8, either. Why? Chromatic aberration is caused, in large part, by the differences in the lengths of the light paths of the image-forming rays. And remember how the volume increased as the cube? right - CA is going to be worse. So they need to go to a different, more complex, design with more elements (pieces of glass, to be shaped and polished). And that's not even allowing for the different element thicknesses forcing the elements to be different distances apart - further throwing off the design.

And that's just a simple 6-element lens design. The 70-200 f/2.8 has 18 elements (not the IS - that has 23!), up from 16 for the f/4.

[robertwgross]

Remember the good old days, about 30 years ago?

We had SLR cameras with f/1.4 lenses as routine, and f/1.2 lenses for a few bucks more. The problem was that they were all manual focus.

---Bob Gross---

[Andy_T]

Bob, that would be the 50 mm lenses, right?
I wasn't old enough to be interested in photography 30 years ago...

Best regards,
Andy

[blackviolet]

yeah i had a hand-me-down nikkormat and a rollei - the good ol' days (i was only 10....)

anyway i suppose to one little bit in response to adauria's original question - look at the cost difference between 70-200 4.0L vs the 2.8L and then look at the differences in the physical size. imagine that same lens going to 2.0, 1.4, 1.0 - lens size going up and price to boot...

[Jesper]

f/stop is... the measurement of the relationship between focal length and aperture size (how big the hole is). So just ... for second... imagine f/1. It's exactly as wide as the focal length. I'm no engineer, but I can imagine how much it will cost to make it that big and still, as others have said, retain sharpness and colour/contrast.
Exactly. So imagine a 300mm f/1 lens. The aperture hole on such a lens has a diameter of 30cm, or almost 1 foot! Can you imagine how big and heavy such a lens would be? :shock:

[grego]

Exactly. So imagine a 300mm f/1 lens. The aperture hole on such a lens has a diameter of 30cm, or almost 1 foot! Can you imagine how big and heavy such a lens would be? :shock:

It would have its own tripod mount with wheels on it so you can push it. :D

[robertwgross]

Bob, that would be the 50 mm lenses, right?
I wasn't old enough to be interested in photography 30 years ago...


Yes, my 50mm lenses were either f/1.4 or f/1.2, and the longest lens that I dreamed of went to about 200mm. Ektachrome 64 and 100. Ektachrome 200 if we wanted to go crazy.

Ahh, those were the days!

---Bob Gross---

[blackviolet]

Exactly. So imagine a 300mm f/1 lens. The aperture hole on such a lens has a diameter of 30cm, or almost 1 foot! Can you imagine how big and heavy such a lens would be? :shock:

bah! - after carrying the 1dmk2 & bigma around so much over the last year, i think i could hand-hold anything for a bit... :p cha, right...

i was carrying the 10d (no grip) & 50 1.8mkii as a second cam on the weekend. when picked it up to take a shot (after putting the 1dmk2/bigma combo down) and smacked myself in the bridge of the nose & eye so hard it left a mark :o