Crop Factor and Aperture

[Wakalimasu]

Wow I didn't know I had to multiply the crop factor by the aperture to get the FF equiv haha.

All this time I thought my 17-55 F/2.8 on my 70D was a 27-88 F/2.8 but it was really a 27-88 F/4.5 FF equiv in order to achieve the same bokeh quality. ><

The more you know! :o

Tony Northrop explains it pretty good in this video.

https://www.youtube.com/watch?v=DtDotqLx6nA

[dirtsniffer]

I also did not know that

[msommers]

Check out Mamiya 1.9!!!

[blitz]

I don't like his views on ISO, and I really don't like calculating equivalent aperture as 2.8 is 2.8 as far as light transmission and shutter speeds go. The 'equivalent' only applies to DOF and bokeh.

[firebane]

Most digital cameras out there are a 1.6 crop sensor. The higher end $$$ cameras are full frame sensors.

People don't really understand this until you start looking at comparisions of full frame vs crop images

http://digital-photography-school.com/full-frame-sensor-vs-crop-sensor-which-is-right-for-you

[Wakalimasu]

No, no. I understand what a crop sensor is. I just never understood how bokeh/DOF was affected by the sensor. In order to get the same quality of blurness I would need a significantly faster lens than I would on a FF. Also I like how he hit on the point on how most camera manufacturer, like that Olympus example, tries to trick you into thinking you have a 28-300 equiv @ F/2.8 when in reality you are getting a 28-300 F/13. You will not get the same bokeh. You will still get the same quick F/2.8 aperture though.

[D'z Nutz]

They're not trying to "trick you" into anything. F/2.8 is an indication of aperture/light transfer of the lens and that's exactly what you are getting, regardless of the size of the medium. Aperture is not an indication of DOF. The perceived greater DOF is an effect of the crop, not the lens.

And it sounds like you're using bokeh and DOF interchangeably. They're not the same thing. Bokeh would not change just because you're looking at the image closer.

[Mitsu3000gt]

2.8 is still 2.8 any way you look at it, it's just the perceived DOF that applies to what he's saying. That is why f2.8 on FF is very shallow and f2.8 on a 1/2.3" P&S or a cell phone still has pretty well everything in focus.