50mm vs 40mm pancake?

Hello everyone! I'm an aspiring photographer on a tight budget. I have a 50D, and my kit lens crapped out, so I've been shooting with my sigma 70-300... Hoping to save up for a more versatile lens. But, it's just not cutting it anymore, I need more flexibility in the meantime.

I've been thinking about getting the 50mm 1.8, just to get me through, but came across the 40mm pancake and I find the portability very attractive. And yes, I know on my camera, they are actually longer focal lengths.

My question is, would the 40mm be adequate for portrait photography? I'm mostly doing friendsand family right now for practice. I think I definitely want to get the 40mm at some point to make my camera more portable for everyday, but if the 50mm is better, I'll start there. They're both so affordable... It's just a matter of starting with the 50mm, or not.

Thanks!

The whole reason to buy the 40 is because its compact and light. The 50 is a better option as a portrait lens because its longer (less tendency toward perspective distortion from working too close) and that at 1.8 you get shallower depth of field and more background separation. The 40 is probably built a little bit better, but you are buying for function at this point.

I own a 50 1.4 and a 40 2.8. The 50 sees a lot more use than the 40. Really, the 40 sees very little use these days. I can't slip a 70D w/ a 40mm into my pocket. If I was walking around all day with a 100-400 and wanted something wider to carry in my pocket, but didn't plan on using then it would be nice option. However, as nice as that sounds, you still have to figure out how you are going to put the 100-400 (or 70-300) while you have the 40 on the camera. This generally means you're going to have to have a bag and if you're going to have a bag, then you might as well bring the lens you really wanted (be it a 50 f1.8 or 1.4 or even a 35 f/2 IS) rather than the compromise the 40 can be.

Now, I'm not saying it's a bad lens, it's a great lens. However, it's slow for a prime and it's portability is overshadowed by the camera still being rather bulky. I still own one, but I'm just not using it. I'll probably sell it when I have some more free time.

I'm a mom who carries a big purse around as it is, even just a little smaller is helpful to me! But it sounds like the 50mm is just that much better, which is my current goal. Thank you for the input!

In terms of weight, 50mm f1.8 and 40mm f2.8 are identical (130g). The 40mm is shorter, but compared to the camera size (50D) this should be a minor consideration.

I agree with others here that the 50mm on a crop works reasonably well as a portrait lens, whereas 40mm doesn't really fit into any established category - too slow for a prime, too slow and short FL for a traditional portrait lens, too long on a crop for environmental portrait lens, etc.

When I started shooting portraits, my one and only model (my wife) sat for a test using different focal lengths equivalent to popular primes (with the 18-200). Anywhere from 135 or thereabouts to 18.

Reviewing the photos afterwards from the longest to the shortest, at 38 mm (I was going for 35) she said icily:

'Loose it'

Then I went 28 and she got up... 'no need to stay any longer...'

And that on a crop...

I get tickled with one of these best focal length for portrait threads gets underway and someone starts advocating the 35mm on full frame for portraits. When pressed for evidence they always post a shot of some hot little skinny model, for some reason they more often than not seem to be asian. I always think, she would look great with a fisheye even, but for the people I shoot there is a min FL/working distance.

LeanneC wrote in post #16893050
I'm a mom who carries a big purse around as it is, even just a little smaller is helpful to me! But it sounds like the 50mm is just that much better, which is my current goal. Thank you for the input!

Have to disagree; the 50/1.8 is NOT better than the 40. Sure, it has a wider aperture, but it is soft until you stop it down to f/2.8 anyway. The 40 is sharp wide open, and since your only lens is a telephoto you could probably use the extra 10mm on the wide end.

MakisM1 wrote in post #16893531
When I started shooting portraits, my one and only model (my wife) sat for a test using different focal lengths equivalent to popular primes (with the 18-200). Anywhere from 135 or thereabouts to 18.

Reviewing the photos afterwards from the longest to the shortest, at 38 mm (I was going for 35) she said icily:

'Loose it'

Then I went 28 and she got up... 'no need to stay any longer...'

And that on a crop...

Sorry, I'm a total newb... What's the effect on the subject with shorter focal lengths? Bad, obviously, but in what way?

I just feel that I'm constantly shooting at 70 and backing up a ridiculous amount to get everything I want in the frame!

timbop wrote in post #16893682
Have to disagree; the 50/1.8 is NOT better than the 40. Sure, it has a wider aperture, but it is soft until you stop it down to f/2.8 anyway. The 40 is sharp wide open, and since your only lens is a telephoto you could probably use the extra 10mm on the wide end.

The sigma I have is a f/4.0 and I don't often go even that low. I'm not currently worried about needing the extra f-stops... The extra 10mm would definitely come in handy, but not at the expense of the ability to take good portraits. Could the 40mm work for portraits, in your opinion?

Thank you in advance to everyone for your experienced opinions! I really appreciate you taking the time.

Agreed with timbop. The pancake 40 is sharp wide open while the cheaply fifty has to be stopped down. It really is up to you which FL works for you. That's the beauty with interchangeable lens system. New technology in lens designs now allow lenses to be sharp wide open compared to older designed lenses.
I find the bokeh of the 40 superior to the 50 1.8 at same fstop.
Having said that everyone should own a 50 1.8 once.

I like the 50mm but don't really trust it. I can shoot 10 photos and have to pitch 7 of them for focus error even if I did the repeated half-press dance. I don't have that problem with any of my other lenses.

I can't speak for the 40mm. I've never even seen one in person, let alone used it.

If you like the idea of carrying your camera in your purse, get the 40 and a LensCoat Body Bag case for it. You can fit your 50D, with the 40 attached, in that case and then throw the whole thing in your purse and know it is fairly well protected.

LeanneC wrote in post #16893717
The sigma I have is a f/4.0 and I don't often go even that low. I'm not currently worried about needing the extra f-stops... The extra 10mm would definitely come in handy, but not at the expense of the ability to take good portraits. Could the 40mm work for portraits, in your opinion?

Yes, but not for head shots though. for waist-up and wider, it will be good.