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10-20-2007, 10:39 PM   #1
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Help choosing lens: 40mm or 50mm

I'm racking my brain trying to figure out which lens I want. I'm looking for a decent lens for portraits and walking around that will work in low light situations. I'm also on a budget. I've read great things about the DA 40mm f/2.8 Limited and the FA 50mm f/1.4. On the one hand, the 40mm has great contrast and sharpness. The 50mm offers the larger aperture. I'm torn. Any thoughts?

10-20-2007, 10:44 PM   #2
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I own a 50 1.4...

I couldn't suggest either one for sure but, even though the 50 has larger aperture, i don't recommend stopping down that much. From 1.4, up to 2.8, the photo is very soft. So, you might end up not using that end anyways (as i have ended up doing). The max aperture i use on my 50mm is 2.8. If your primary concern is opening the aperture for low light, then i consider them the same because I wouldn't be happy with the soft photos i get at larger than 2.8. I think the 50 is also a little slow on focusing in low light. On the other hand, the 50 does translate into a pretty comfortable range for candid portraits (i.e. in a normal sized room or something like that). I cannot tell you much about the 40.

Last edited by Tingchaleun; 10-20-2007 at 10:50 PM.
10-20-2007, 10:48 PM   #3
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Having had the 40 and 50 and as well the 43. I'd suggest the 43 as the better lens. It combines the best of both and I sold my 40 when I compared it to the 43mm. In my book the 43 wins over the 40 and is the better FL than the 50 for many portraits. I will say though that I find the 50 better than indicated above.

Last edited by Peter Zack; 10-22-2007 at 01:16 AM.
10-20-2007, 11:08 PM   #4
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The 43mm looks very tempting, but the price tag is almost double the 40mm. Ugh, my brain will explode before I reach a decision.

10-20-2007, 11:15 PM   #5
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Sorry to add to the confusion. But to be frank, I just had a chance to use an 85mm A* f1.4 and it is proof positive that you should, whenever possible get the best you can in each focal length. The lens is the determining factor on great vs good vs average. This gear will last a lifetime and if it means saving for an extra month or so it's worth the wait.
10-20-2007, 11:39 PM   #6
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QuoteOriginally posted by Peter Zack Quote
The lens is the determining factor on great vs good vs average.
Greetings

Best lens is worth nothing when one lacks experience ? Are not you spreading LBA, btw, what exactly is LBA ?

Take care

andy
10-20-2007, 11:47 PM   #7
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Agreed that experience and understanding technique is very important. If you are a casual shooter then maybe the top end lens is not what you want or need. It may be just a waste of money. But if you have the opportunity and desire to get the best you can afford then why not? These K series cameras are excellent and for me, getting the best out of them and myself is a daily endevour.

LBA stands for Lens Buyers Addiction. Am I spreading it? Nope I don't think so. Trying to offer some advice to the OP on which is best. If I said buy all 3, then that's pushing LBA!
10-21-2007, 02:56 AM   #8
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F/2.8 is 2 stops slower and even though the dof is very narrow it can be a "life saver" . For aps-c I'd use the fa 35 f/2.0. A compromise of faster lens and closer to the normal prime fov.

10-21-2007, 03:26 AM   #9
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QuoteOriginally posted by Peter Zack Quote
Sorry to add to the confusion. But to be frank, I just had a chance to use an 85mm A* f1.4 and it is proof positive that you should, whenever possible get the best you can in each focal length. The lens is the determining factor on great vs good vs average. This gear will last a lifetime and if it means saving for an extra month or so it's worth the wait.
I used to think that lenses are things we stick on the front of our cameras. Then one day I came to understand that cameras are things we stick on the back of our lenses.
10-21-2007, 04:36 AM   #10
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Just another opinion

QuoteOriginally posted by Tingchaleun Quote
... [E]ven though the 50 has larger aperture, i don't recommend stopping down that much. From 1.4, up to 2.8, the photo is very soft. So, you might end up not using that end anyways (as i have ended up doing). The max aperture i use on my 50mm is 2.8. If your primary concern is opening the aperture for low light, then i consider them the same because I wouldn't be happy with the soft photos i get at larger than 2.8.
I hear this every so often about the FA50, and I disagree. We all have different opinions of what qualifies as "soft," of course, and maybe your copy of the lens performs differently than mine. But I believe that most of the time when someone claims that the 50 is "soft" below f/2.8, s/he is really complaining either about (1) the extremely shallow depth of field when the aperture is so large, and/or (2) a very slight front- or back-focus issue with the lens, which of course becomes more visible at large apertures with the shallow DOF. For what it's worth, I don't find my 50 "soft" at all.

Yes, I too try not to use the 50 below f/2.8 or f/3.5 unless I have to -- most of the time an extremely shallow DOF isn't particularly useful. But I certainly do not consider the 50 "the same" as a lens with a max aperture of f/2.8 -- that, in my view, vastly misstates / understates its capabilities. There's a huge difference (of two aperture stops) where the 50 is usable -- even if not ideal -- and the 40 is, well, not.

As for the OP's original question, the 2 lenses are clearly different, each with its pros & cons. To me, it's simply an individual's choice as to which set of features and compromises -- regarding price, size / weight, max aperture, build quality, and rendering quality -- to accept and which to reject.

Personally, I chose the 50, and don't regret it, but now am very very tempted to acquire the 43mm Limited. (And please, will someone tell me it's perfectly OK to have both the 50 and the 43?)
10-21-2007, 07:08 AM   #11
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YCl, I have both and use both for different things. I shoot the occasional wedding and the 50 makes a huge difference in dark situations like the church. I agree with your comments on the lens (sharpness vs DOF).
10-21-2007, 07:18 AM   #12
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I had tried Fa 50 for 2 month period. The "sharpness" using aperture from f1.4 to f2.8 is quite inconsistent. I believe this is due to certain lighting conditions that can make it worse ...

However I feel the copy I tried had significant CA (some FA 50mm were reported little problems with CA)

I had tried Da 40 in Taiwanese camera shops and I preferred Fa 50mm simply for its faster aperture as a prime.
10-21-2007, 09:13 AM   #13
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QuoteOriginally posted by Mike Cash Quote
I used to think that lenses are things we stick on the front of our cameras. Then one day I came to understand that cameras are things we stick on the back of our lenses.
Very true, which is the 1 reason why I'm hesitating on adding a Sigma SD14 body to my collection.
The body might be better than my K100D, but I don't have the selection of quality glass.
No I'm not selling my Pentax gear if I add another brand to my collection.
10-21-2007, 11:18 PM   #14
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Da40

QuoteOriginally posted by synnyster Quote
I'm torn. Any thoughts?
Get the DA40 it's a newer design, made specifically for digital. It's a tiny, affordable gem.
10-22-2007, 01:29 PM   #15
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I just started looking at the Tamron 28-75mm F/2.8 SP AF Macro XR Di LD-IF as well. This seems like a pretty versatile lens that could replace my kit 18-55 with a nice constant 2.8. Do any of you have opinions about the Tamron? Macro ability is something nice to have. But at 2.8, it's not as fast as the 50mm.
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