FD to EOS/EF adapter

[Busted Knuckles]

Anyone try one of these creatures.

[neuroanatomist]

They're not great. There are two kinds - ones with no optics that preserve the IQ of the lens, but you lose the ability to focus to infinity (sort of like a very short extension tube), and ones with optics that preserve infinity focus, but the IQ takes a hit, usually a big one because of the cheap optics in such inexpensive adapters.

There's a third option for some lenses - the ultra thin Ed Mika adapters for FD tele lenses, and his conversion for the FD 55mm f/1.2.

More here: http://www.canonrumors.com/tech-arti...-your-ef-body/

[Busted Knuckles]

converting the long telephoto would be the target. Thanks for the quick reponses.

Mike

[Dr Croubie]

In that article, Ed Mika talks about the long telephotos. They're a lot easier, apparently you can just loosen a set screw to focus 'past' infinity, then they'll focus to infinity on any EOS body...

[Busted Knuckles]

Well maybe it was dining w/ a physics professor.....

We started thinking about hacking a small senor 14/16 megapixel P&S of some sort and then mounting a DSLR type lense. The idea is to use the "power of the crop" to shoot down the middle of the lens, fast f stop, onto a small sensor and get a very high effective length lens.

As this will be daylight only, not concerned about high ISO noise, pixel density not the big concern.

I expect the first prototype is going to be a "Frankencamera"

Any thoughts?

As it will be done w/ small wrenches just call 211

[Dr Croubie]

This time i'll show my maths...

Powershot A3300 IS, 16MP 4608*3456 sensor, 1/2.3".
So put that in 2:3 crop is 4608*3072.
1/2.3" sensor is 6.62mm*8.83mm, in a 2:3 crop that's 8.83*5.89mm.
That gives a crop factor of 36/8.83 = 4.07.
600mm f/4.0 lens becomes 2444mm f/16.2
To get the same pixels on target you'd need a 235MP FF sensor.
I think that's right.

Anyway, you're going to be well into the diffraction-limited region of the sensor at that stage, not sure how bad it'd be though, I want to see sample pics!

[Dr Croubie]

If you're going to put it onto a P&S sensor, you could always just go with a P&S to begin with, forget about the FD-EOS side and just get an FD-NEX or FD-4/3rds adapter, and either a NEX or PEN or Lumix camera. Try here, for example.

Also depends how small a sensor you want? The idea of 14MP on a small sensor is to get a lot more pixel-density (in absolute terms) than a 21MP FF or 18MP APS-C (as many 'pixels-on-target' as a 46MP FF sensor, if i've done my maths right). A NEX-7 may cost more than a 7D on sale, but you get as many pixels on target as a 56.8MP FF sensor.

Starting with the next-size down, you get a (micro-) 4/3rds, a 2x sensor crop factor. Something like the Lumix G3 is 16MP, upscale that to FF size (taking the ratio into account to make it 3:2) and you get 56MP (so i'd go for the nex-7 over that, if it weren't for the pricetag).

Anything smaller-sensor than that again, and you're into hacking something onto a P&S. Like a 14.7MP G10, 1/1.7" sensor is 8.96mm * 11.96mm (11.96*7.96 for 3:2 crop) which is a nice 3x sensor-crop factor. If my maths is right that ends up more like a 117MP FF sensor, that's getting a lot better (and from what i've heard, at iso100 the image quality isn't too bad). So mounting, say a 600mm f/4.0 lens onto that G10 sensor, in FF-equivalent terms it's going to look like a 1800mm f/12 (DOF-wise) lens. That's not bad.

I have no guarantee my maths is right, anyone want to check? (fixed once, think it's better now)