How the mighty have fallen ...

[dee]

Just bought a good Vivitar 80/200 in MD mount for £3.55 , just over £7.00 with post .
It will be 160/400 on 4/3rds , gotta be useful !

[Mark Vaughan]

I didn't realize that the focal length would change that drastically when switching formats. What Four-Thirds system do you use? I have a Nikon 5700 - not sure what the format is though.

[Deleted]

Depends on the Camera.

On Nikon DX sensors, for instance, a lens that is 35mm on a film camers will cover the same area as a 50mm. Take the focal length of a lens, divide by two and then multiply by three. I've never sorted out the forumula for other digitals.

Bear in mind if you put a 35mm lens on a Nikon it's still that focal length. And has the depth of field of a 35mm lens. But the lens only has the coverage of a 50mm--there are areas on the edges of the lens outside the coverage of the sensor.

This is nice with telephotos because of you have an 80-200 f4 zoom for a Nikon film camera it cover the same area as a 120-300mm f4 on a DSLR. But on wide angle, to get the same coverage as a 24mm film lens you have to use a 16mm lens on a DSLR.

[nikonbob]

Mark

Sensor size can make a huge difference www.cambridgeincolour.com/tutorials/digital-camera-sensor-size.htm .

Bob

[SidW]

The factor for Canon is 1.6, to make it easy just add on half which gives the same result as Wayne's: 80mm on DSLR works like 120mm on 35mm full frame.

[dee]

Factor for all 4'3rds and micro 4'3rds is x 2 , so a neat little 135 / f 3.5 becomes a light compact 270mm.
By the same token , the size of the viewfinder is halved ! I thought my Leica IIIc was squinty - I have to focus through the Dig 3 , but the 135 is usually used at infinity - problem solved . 400 will be a 1st for me !
A 50mm on Emma the M 8 is a super 67mm - which I quickly began to like a lot - but I am into dee'tails .
A 35mm is around 46 which is handy .