Possible Dumb Question - Aperture Modifications???

just got to thinking the other day, "what if you could swap out aperture blades from 1 lens to another?"

such as using a 24-70 f2.8 lens w/ a 35L f1.4 aperture???

is this possible? is this a stupid question not worthy of an answer???

complete curiosity here as i dont own a 24-70 & no longer own a 35L


thanks though

What would be the point? It isn't like putting a bigger aperture in a slower lens would make the slow lens work like a faster lens. The entrance pupil is going to start becoming the restriction.

JeffreyG wrote in post #16052851
What would be the point? It isn't like putting a bigger aperture in a slower lens would make the slow lens work like a faster lens. The entrance pupil is going to start becoming the restriction.

reason for the question...it was a simple thought that popped in my head randomly the other night...thanks

Probably not. Just because the aperture blades are designed around the optics and barrel and are all different sizes. I suppose if you crafted your own to fit in the area designed by Canon to take the aperture blades, it could work.

It guess it would be useful if you were replacing straight blades with curved blades for nicer boken. On the other hand if you already have a lens with curved blades(assuming they'd fit the other lens) it's probably already a better overall lens.

ExplicitSnow wrote in post #16052820
just got to thinking the other day, "what if you could swap out aperture blades from 1 lens to another?"

such as using a 24-70 f2.8 lens w/ a 35L f1.4 aperture???

is this possible? is this a stupid question not worthy of an answer???

complete curiosity here as i dont own a 24-70 & no longer own a 35L


thanks though

I apologize if this sounds condescending, but it seems like you are thinking about the redesign of optics created by professional designers and engineers without the appropriate skill or knowledge required to properly understand their original design choices. If this is not your area of expertise what would you hope to gain over the original design of experienced engineers?

ExplicitSnow wrote in post #16052865
reason for the question...it was a simple thought that popped in my head randomly the other night...thanks

Look at it like this. There is a reason why fast lenses have large objective elements. It's to let in more light. Compare a set of good night binoculars to a standard pair. The objective end is huge so that they gather more light to allow you to see at night, even under starlight. Look at the size of the 17-55 vs. the 18-55. That added size is what is needed to bring in an additional stop of light. The extra 1 mm of field is a slight factor, but most of the difference in the objective end of the lens is for light gathering. Even if you could make the blades fit in the 18-55 (no way, but if you could), it wouldn't make a bit of difference in the speed of the lens.

The easiest way to understand this is as follows: If all you had to do to make a lens faster was stick a bigger aperture in it, don't you think Canon would have done that in the first place?

The EF-S 18-55 is $150. The EF-S 17-55 is $950. If you could just take the $5 aperture from the 17-55 and put it in the 18-55 and get the 18-55 to be a constant f/2.8 lens, then I'm pretty sure that is what Canon would have done.