How can Oly EM-1 compete when FF DSLR with L zoom goes for $2300?

Started Sep 1, 2013 | Discussions thread
ultimitsu
ultimitsu Veteran Member • Posts: 6,650
Re: Size, telephoto, not much better IQ...
1

Elix wrote:

ultimitsu wrote:

Elix wrote:

ultimitsu wrote:

Elix wrote:

Not really.

Canon 500mm f/4 II USM - $10,400

14.48 x 38.45 cm - 3.19 Kg.

OR

Olympus 90-250mm f/2.8 ED Zuiko - $6,000

12.47 x 27.69 cm - 3.69 Kg

The 500/4 is a far superior lens and one full stop faster.

Can you tell me how f/4 is one stop faster than f/2.8 ?

The "F" in canon F/4 is 500, the result is 125mm aperture opening. The "F" in oly F/2.8 is 250, the result is 89mm aperture opening, which passes only half as much light as 125mm.

So to get the same amount of light onto the sensor, you shutter speed has to be twice as long/slow on the 250 F2.8.

Well, you shoudl educate youself a little more,

please do

being the sensor smaller, it does not need the same amont of light.

please elaborate,why does it not need the same amount of light.

However, it will need the same amount of light per-pixel.

Right, a 16mp OMD's pixel is 1/4 the size of the 14mp D4, but to generate the same picture it needs the same amount of light per pixel as the D4, is that what you are saying? if so you are completely right. And since 250/2.8 only passes 1/2 as much light onto the sensor as 500/4, you need shutter twice as slow.

Pretty cool huh?

There is no f/stop equivalence across different sensor (or film) sizes (despite what you think) . f/stops are what they are, end of it.

Can you tell us what you think is the "F" and what is the "stop" in F/stop?

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