A usual photographer's dilemma

[Abhinow79]

Hey Mark,


Thanks a lot for your response





Cheers[]

[Rodger]

I don't haveexperiencewith any of thelensesyou mentioned, but if I can suggest.. Why not go for a 70-200mm f/2.8 (no IS) [$1250], and the 35mm f/2 [$300]. I realize that puts you over budget, but only by 50 bucks. And from what I've seen, the 70-200 f/2.8 does.. does.. does.. create bokeh


Just my take on the situation. Isupposeit depends on your shooting style. I know that the 70-200 f/2.8 is on my list though.


-Rodger

[Colin]

I wouldn't argue that a f/2.8 doesn't have more bokeh potential than f/4, though if you stumble just the right way, and can pick and choose your backgrounds, and keep your subject far closer than the background, it's not impossible to get a lot of background blur stopped down substantially...





This was at f/5.6 on a crop body XT, making it effectively f/9 compared to a full frame body.


OTOH, you also need to keep in mind that f/2.8 on a crop body is going to be equivalent to f/4.5 on a full frame body too, so... maybe that's an even stronger nudge. I don't know.

[Abhinow79]

Meanwhile I had no idea that 1.6 bodies also decreases the aperture width of the lenses. I thought that a f 2.0 lens would be constant f 2.0 on both cropped and full frame body! That's bit of info is revelation to me really

[Colin]

Sorry. I know it was addressed in another thread where I think you brought it up, but I was referring to the depth of field/bokeh. The smart guys pointed out that the 1.6 crop not only multiplies the 'effective' focal length from the field of view standpoint, but also affects the 'effective' aperture from a depth of field and total light gathering perspective. The actual light intensity hitting the sensor is the same.


I apologize.

[Daniel Browning]

Meanwhile I had no idea that 1.6
bodies also decreases the aperture width of the lenses. I thought that
a f 2.0 lens would be constant f 2.0 on both cropped and full frame
body!

50mm on XT and 50mm on full frame result in very differnet images. The angle of view is very different. To get the same angle of view requires using 80mm on full frame. So it can be said that 50mm on XT is equivalent to 80mm on full frame.


f/5.6 on XT and f/5.6 on full frame result in very different images. The depth of field, diffraction, and total amount of light is very different. To get the same DOF, diffraction, and light requires using f/9 on full frame. So it can be said that f/5.6 on XT is equivalent to f/9 on full frame.


There is a thread going on about this right now:


Crop factor and f/stop

[Abhinow79]

. Thanks Rodger for your input. 70-200 f 2.8 is high on my wish list , but as it costs USD 1800 in Indian money equiv . I am off my budget with this lens. which is why 135 L is attracting me so much. But buying a lens is always a compromise, as I had heard..and now experiencing it for self.