Originally posted by dtmateojr Going wide open is not the only solution and going shallow DoF is not always the best idea for a particular situation. Post a sample shot here of why you needed to go for f/1.8 so we can discuss better.
I don't have a photo that perfectly describes what I'm talking about, as I don't shoot wide open all that often (as you've said, though, the practice is heavily used and abused)... but here's an example:
I'm in a function room with other family members and I have my 50mm f/1.8 on my APS-C camera. There is very limited room between my subject and the far wall with all it's visually disturbing elements. I want to blur that as much as possible. I can't move back much further than I have already, because we're in the confines of a room. So I decide to shoot wide open, focusing on the eyes, with the understanding that I'm going to have shallow DoF - which may not be ideal for my subject - but is best for my background, and I can make it work for the subject. Also, f/1.8 works well for my lighting situation.
Given all of that...
Since I can't move back any further, or get my subject to move further away from the back wall (because it's not a prepared shoot - I'm taking photos as I go), how else can I achieve broadly equivalent blur - whilst maintaining the same perspective distortion - other than going for a wider lens and wider aperture?
I'm not trying to get into an argument, my friend... I *agree* with you that in many, many situations, shallow DoF isn't necessary or is poorly utilised - but the desire remains by *many* photographers to be able to achieve it nonetheless. And if we circle back round to what I was initially talking about, in my view the difference between m43 and FF in being able to create shallow DoF is pretty large, given the same subject and circumstances (unless you have a much faster lens on the m43 camera). Hence, APS-C fills a middle ground between the two.
---------- Post added 03-16-2016 at 09:54 PM ----------
Originally posted by dtmateojr [/COLOR]have you seen the Oly 45/1.8? It's ridiculously tiny and the DoF you can get from it is paperthin.
At what subject distance, though? Is it, for instance, as paper-thin as a 55mm f/1.4, lens at f/1.8, on APS-C, or a 90mm f/1.8 on FF, at the same distance?
EDIT: Again, I'm not saying these are always practical concerns. I'm not even saying they are *regularly* practical concerns. What I'm saying is, many people want shallow DoF capability. The difference between m43 and FF in this respect is quite big, but less so between APS-C and FF. That's all I'm saying.
EDIT: The Olympus 45mm f/.1.8 you mention looks like incredibly good value, and appears to perform awfully well from the reviews!
FINAL EDIT (of *this* message): OK, see attached. This was taken on my FF camera, 60mm at f/3.5 (you'll have to forgive the quality - it was ISO 8000, and the image is heavily compressed to < 100k JPEG and then loaded onto the site which softens things!). I was testing my camera and lens at the time, sat on the sofa (so I couldn't get further back), and the table is in a fixed position on the floor. How would I get roughly the same field of view, perspective distortion and blur on m43 without (a) using a lens that could do 30mm at f/1.8, or (b) moving either myself or the subject? Now, let's pretend the mug is a sign I want sharp, in front of buildings I want completely blurred... etc. etc.