DPChallenge: A Digital Photography Contest You are not logged in. (log in or register) 
 

DPChallenge Forums >> Hardware and Software >> Considering the Sigma 18-50mm f/2.8: Any Comments?
Pages:  
Showing posts 1 - 9 of 9, (reverse)
AuthorThread
 02/06/2006 10:17:23 AM · #1
My current walk-around lens is a 28-80 f3.5-5.6 that I harvested from my film SLR. I have the Tokina 12-24, but I want better coverage in the lens that I leave mounted, so I'm looking at the 18-50ish range that comes as the 'kit' lens on most DSLRs today.

However, as I get more serious about my photography, I have promised myself not to buy any more slow glass... so I had already eliminated the 18-70 Nikkor that's the current D70 kit glass. Then I look at that lens here and the number of incredible photos taken with it is insane.

However, a lot of what I will do is outdoor portraiture... I have a client booked for March to do sports team portraits, for example. In my mind the extra aperature will come in handy in those situations, giving me minimal DOF, and nice fast shutter speeds. Looking through some of the portfolios here I'm nervous that I'm going to end up with exposures at 1/15 and 1/30, probably not ideal for gum-chewing teens.

So then I looked at the Nikon alternative. The clear winner is the Nikon 17-55 f2.8 G-IF-ED. Incredible glass, plenty fast, bonus Internal Focusing... but the cost: $1200, OUCH! My wife, another photographer, has already informed me there's no way we're spending that much on a lens.

So then there's the Sigma 18-50. Nice constant 2.8, not Internal Focusing, which is fine with me. Price is good too, more than half the Nikon. However, there seem to be complaints of softness at f/2.8 that clears up by f/4. Well, what's the point of fast glass, if you can't use it?

Are there any other contenders in this focal length that I should be looking at? I don't want to go all the way to 24-70, That's about what I have now (28-80) and I miss the wide end of the zoom from time-to-time.

Should I just bite the bullet and get the Nikon lens? Or is the Sigma's "softness" not really that big of a deal when we talk about a 8x10 print?

Thanks!
Andrew
 02/06/2006 11:15:56 AM · #2
Lots of things come to mind..

All lenses are sharpest in the middle of the the aperture range. SO if max sharpness is the issue, then 5.6 or so is best. Super sharp for portraits is not a great thing. Maybe ok for kids, but old folks - no way ;)

The sigma 18-50 2.8 I have for canon IS internal focusing.

Blurred backgrounds are a function of aperture and distanec to the subject/BG. I can get teh BG OOF with my tamron 24-135 3.5-5.6 probably more easily than with my sigma 18-50 2.8. With one person anyway. Not sure I could get the BG OOF on a group with either lens - the wider the angle of the lens the more DOF you get at a given aperture.

have you a 50 1.8? that might work very well.

I don't see any pics from my sigma at 2.8...i'm sure i must have some. My outdoor shots are 3.5 to 4 it seems, and my wedding shots are all flash ones, so 5.6 or so. Most of my outdoor work i now do with my tamron 24-135. to get 2.8 ourtside you might need ND filters.

if i need shallow DOF i use my 50 1.8 or 70-200 2.8. Sorry i can't be more help...

Message edited by author 2006-02-06 11:17:21.
 02/06/2006 09:53:56 PM · #3
You've been more help than you think.

1) Point taken that sharp and portraits don't mix. General question: Is a 3.5-5.6 also less sharp at 3.5-5.6? Do you need to stop that lens down to 4-6 in order to get sharpness back?

2) Point taken about the DOF relation to Focal Length. As well.

3) I do not have a 50 1.8, but I have a 60 2.8 on the way to be a general portrait lens.

4) I'd be wondering what kind of shutter speed you're mixing with that 3.4 to 4 aperature if you're doing an outdoor shot... like the bride and groom on the church lawn or steps or something. That's going to be very similar to my outdoor sports portraits.

5) I'll probably end up using my 60mm 2.8 for the sports portraits, so it goes back to the original question: a good general walk around lens.

Now, based on my further research on the topic, there are three more contenders:

The AF-S DX Nikkor 18-70 mm f/3.5-4.5G IF-ED, the D200/D70 kit lens which is "only" $340 but gets very good reviews.
or
The Nikon AF-S DX Zoom-Nikkor 18 - 55mm f/3.5 - 5.6G ED, $160, and Ken Rockwell raves about it. However I'm starting to worry about the aperature at this point.
or
Nikon AF-S Nikkor 18 - 200 mm f/3.5-5.6G DX ED VR, which splits the difference at $750, gets rave reviews about the VR, but is out of stock everywhere except Mars.

AAGH! Instead of narrowing down options, I've found 3 more. Come on Nikon owners... lend me a hand here!

Edit: I wonder if, since the lowest ISO on the Nikons is 200, I need to worry less about the 2.whatever glass. Hmm...

Message edited by author 2006-02-06 21:55:46.
 02/06/2006 11:41:34 PM · #4
I have the Sigma 2.8 18-50. I like it and it is very sharp in the middle apertures.

I currently have a picture taken at f22 that isn't as sharp. I haven't done a subjective test though. I'm very happy with it as an all round lens (the only one I have) as I like the advantages of a fast lense (bigger DOF or faster shutter speed) and I like wide angle.
 02/07/2006 12:25:02 AM · #5
The sharpest a lens is in the middle aperture range - so going to f22 does not make it sharper, and might make it less so as the light bends around the small opening the light has to bend more to get to the sensor, and does not hit it as straight.

As for hte nikon lenses - any 10:1 zoom seems to have issues at one or both ends with distortion or pincushioning. For somethings it won't be noticeable, but open it to 18 and take a pic of people infront of a doorway and it might get ugly as the door frame bends about the place ;) I read rave reviews about one of the 18-200 lenses (foret which one) and then I saw a shot of a window and the distortion was beyond my tolerance levels.

The 18-200 VR is highly anticipated - I have not heard anything since on it, no reviews or feedback or anything.

The 18-70 I've heard good things about. It might be a good range for a walkabout lens. I played a bit with the canon 17-85 IS lens ($600) and it is a nice lens,but the Tamron 24-135 has more range for less money and is rated better optically, so i went that way and it's great.

18-55 and $160...sounds like low end consumer glass to me.

Do yourself a favor and check out this lens!

FM reviews on it here - rates 9.3 on a 10 point scale. 100% of reviewers/users recomend it.
02/07/2006 12:43:27 AM · #6
Tamron 28-75mm f2.8

Best zoom I have ever had the pleasure of using, but then, I admit I have never used any "L" glass. Actually I don't even use this lens that much, as I'm usually using MF specialty lenses for most of my stuff, but I put this lens on whenever I'm stepping out because I know it can deliver the goods across the whole zoom range.

It is a good lens for outdoor portraits too. Even on very bright day you can typically use the f2.8 (iso 100) on the long end of the lens. And who said portraits and sharpness don't mix? Maybe for the aging set :) I don't find sharpness a problem with childrens portraits.

//www.pbase.com/mcmurma/image/40519297

I meant to add that I still own a sigma camera, and a few Sigma lenses (but not the 18-50). And while some of their lenses are quite good (70-300 APO), many of the EX class (yes, their best) infuse the image with a yellow cast that is most distasteful. Apart from that they make good lenses, and the 18-50 is well regarded for sharpness. But I personally hate the yellow and much prefer the color rendition of tamron lenses. One last thing, you will like having a longish focal length for getting close-in on portraits, 75mm is usually just enough.

Message edited by author 2006-02-07 00:59:16.
 02/08/2006 03:44:42 PM · #7
Back to this discussion...

I don't want a lens that starts at 24 or 28mm... I currently have a 28-80, and a 12-24. I use the 20-28 focal length a fair amount (that's effective 30-42, in 35mm) and I hate switching lenses over that range (and the 4mm gap).

Ken Rockwell's site actually gives the $160 18-55 a better review than the 18-70. But his main complaint seems to be with the camming of the zoom on the 18-70... he states the 18-28 lengths are bunched up within the first little bit of twist on the zoom ring, making them hard to select accuratley. I think I could live with that more than the f-stop hit of the 18-55.

He also has a review of a production 18-200 VR and says it's to die for. But I think I'm going to wait a bit on that one.

So I think I've narrowed it back down to the Sigma 18-50 at $469 or the Nikon 18-70 at $339. I think I'll take the extra 20mm and the Nikon name over the extra aperature, considering the ease of ISO changes with digital.

Any reason not to? ;)
 02/09/2006 01:12:26 AM · #8
I was out shooting today and did some tests with my Sigma 18-50 2.8 EX DC.
All handheld, ISO400 and untouched - 100% crops, no PP at all. Sve for web at 100K files (70-75% quality). The color comes from the setting sun as it shone into our dining room.
You tell me if this is sharp enough for you? Remember, NO sharpening has been done.

Yes, at f5.6 is is sharper, but that is to be expected.

Is the Nikon a constant aperture lens?
Two thoughts on that, if it isn't (i'm a canon guy, not familiar with the nikon-brand lenses)
1) as you zoom with a constant aperture lens, your aperutre stays the same, so the shutter speed/exposure remains constant. Once you experience this (especially in low light shooting) you LOVE it.
2)you get the same bright viewfinder at all zoom ranges, and brighter than a 3.5-5.6 lens at any aperture. This aids in the camera focusing and you're ability to manually focus if so desired.

Today i visited a church that i'll be shooting a wedding at on the 25th. I had my sigma lens on there and got nice pics at 1/60 at f2.8, at ISO 800 (P mode, the camera chose that ap setting). I can likely shoot at 1/30 at ISO 400 if I hold steady. With a 3.5 lens, you'd have to shoot at 1/30 at ISO 800 (doable)or 1/60 at ISO1600 and get pretty noisy pics. And at 50mm I still get that exposure - the 17-70 is mid way thru it's range so just when you need more shutter speed for 1/focal length you lose speed as the ap closes down.

Many wedding photogs that are flash happy rely on one lens - i know one that uses a $350 canon 28-200 lens, very average, and gets $1000 an hour. She shoots with a diffuser filter so sharpness is not an issue, uses flash so speed is not an issue. It's her style.


02/09/2006 02:57:27 AM · #9
Thanks for your tests. For me this is way too soft at the larger apertures and I am not impressed with f/5.6

Compared to the 18-70: It doesn't even have f/2.8.... A missed shot is a missed shot. I am amazed how many times I shoot with my primes below f/2.8, so the speed is important. Camera shake blur at the 18-70's widest apertures is worse than a bit of softness at f/2.8. That's where the 18-200's VR technology is important, but VR will not help you with a moving subject.

I'd go for the Nikkor 17-55 f/2.8 DX if I needed the wideangle that much, but it is a lot of money. At the moment I'm looking at a portrait range lens like the Nikkor 35-70 f/2.8, often reffered to as the 28-70's little brother. The only thing I don't like about that one (the 35-70) is the push pull zoom and it is non-afs and not a G lens. As far as I understand a G lens works better with off camera flash.

Message edited by author 2006-02-09 03:14:34.
Pages:  
Current Server Time: 12/29/2025 10:09:47 AM

Please log in or register to post to the forums.


Home - Challenges - Community - League - Photos - Cameras - Lenses - Learn - Help - Terms of Use - Privacy - Top ^
DPChallenge, and website content and design, Copyright © 2001-2025 Challenging Technologies, LLC.
All digital photo copyrights belong to the photographers and may not be used without permission.
Current Server Time: 12/29/2025 10:09:47 AM EST.