1. ## EF 10-400mm f/1.2?

I notice that alot of people put ridiculous titles for their threads and it seems to catch people's attention. Hence my thread title.

So I'm wondering if there exists some sort of website or program that you can enter in a given focal length and maximum aperture, even ones that seem ridiculous like 10-400mm with f/1.2, and have the program calculate the approximate size of such a lens. I'm trying to get a more concrete idea of why lens makers don't make lenses with outrageous capabilities like this, if they're even physically possible.

Any ideas? Thanks

2. ## Re: EF 10-400mm f/1.2?

Hi Justin,

Size is an easy one - just divide the focal length by the maximum aperture (smallest F-stop number) to get the minimum lens diameter. So for a 400mm F1.2 you'd be looking at 333mm*

* excluding wheel barrow!

3. ## Re: EF 10-400mm f/1.2?

Hi Justin,

Because Canon, Nikon, et al, are in business to make money, they happen to have chosen lens (and camera) manufacturing as the means.

If they made such a lens, it would be
Very large
Very heavy
Very, very expensive
Probably not very good in image quality - too many design compromises over such a vast fl range

... and therefore no-one would buy one - not a good way to turn a profit in business.

I'm sure someone cleverer than I could work out the front element diameter for a 400mm f1.2 (the limiting factor).

My guesstimates; 450mm long, 250mm in diameter (at front) and about 20kg.

How close am I?

4. ## Re: EF 10-400mm f/1.2?

I'm sure someone cleverer than I could work out the front element diameter for a 400mm f1.2 (the limiting factor).
Colin's right. 400 divided by 1.2 = 333mm. However, it's usually larger to reduce light fall-off and loss of corner sharpness.

5. ## Re: EF 10-400mm f/1.2?

Originally Posted by Dave Humphries
My guesstimates; 450mm long, 250mm in diameter (at front) and about 20kg.

How close am I
That would be close to the F1.6 version

6. ## Re: EF 10-400mm f/1.2?

Originally Posted by Colin Southern
That would be close to the F1.6 version
How does that perform? (I assume you do have one )

7. ## Re: EF 10-400mm f/1.2?

You'll look like this guy. In fact, the 400mm f/1.2 would be even larger as this is "merely" a 200-500mm f/2.8 zoom.

8. ## Re: EF 10-400mm f/1.2?

Oh yeah? Try THIS one for size!

9. ## Re: EF 10-400mm f/1.2?

That's no Canon, that's a cannon!

10. ## Re: EF 10-400mm f/1.2?

Originally Posted by Colin Southern
Oh yeah? Try THIS one for size!

too slow, it doesn't have USM in it

11. ## Re: EF 10-400mm f/1.2?

To slow indeed. only 1:14 and I miss the IS

12. ## Re: EF 10-400mm f/1.2?

Hi Justin,

if you are going for the sigma I suggest a shoulder pad, external electronic live view and a cable remote in combination for more convenience.

And here are some technical stats for the Canon 5200mm mirror tele:

bye
Robert

Wonderful

14. ## Re: EF 10-400mm f/1.2?

by the way, that 16,640mm with a 2x converter on a crop-factor camera!

It would be great for wedding photography ... you could stay at home and still photograph weddings in another part of the country!

15. ## Re: EF 10-400mm f/1.2?

Originally Posted by Colin Southern
It would be great for wedding photography ... you could stay at home and still photograph weddings in another part of the country!
How this is possible...?

16. ## Re: EF 10-400mm f/1.2?

Originally Posted by Colin Southern
by the way, that 16,640mm with a 2x converter on a crop-factor camera!

It would be great for wedding photography ... you could stay at home and still photograph weddings in another part of the country!
You have just caused me to splurk my lunch coffee all over the monitor, you bad boy!!

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