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11-17-2010, 10:15 AM   #1
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Should I return my Sigma 50mm 1.4 HSM ?

Dear Pentaxians,
I bought this Sigma 50 1.4 and still have a week to go for the 15 day return window given by BnH. It is intended to be a second wife of my K7.

First, the good: [skip this if you already know abt the Siggy. I'm saying it all because I feel like boasting about the lens!]. I love that the damn thing is so sharp, I could cut myself if I'm not careful!! Just like everybody else, I'd say the build quality is very welcome, and a pleasure to hold and MF. HSM is buttery. A tad heavy, but reassuring heft. The color rendition is different, but I'd say it looks very saturated (like having a bit of a polarizing filter permanently attached!), and IMO very professional looking and a little warm. (Now, in a challenging lighting situation, this could be a little more of a problem.. but, anyways).

Now, the not so good: I have a gripe about it's AF accuracy. I've read at a lot of places about this lens doing a front focus when the aperture is opened up. Well, I have a copy that does it I know everybody will pounce at me in saying that that should not be a problem coz I have the k7 with the AF microfocus adjustment. But, my second problem is that this FF is different for different subject distances. Here's what I can summarize based on some real life and otherwise (tripod - IR remote - mirror up - non stabilized - test chart) testing.
  1. Indoor, K7 set to 0 microfocus adjustment:
    1. subject at greater than 6ft:
      1. F2.8 and smaller, AF seems to be very accurate. Sharpness... don't you dare ask!
      2. F2.0 and larger, AF is more and more front as aperture widens.
    2. subject at lesser than 3ft:
      1. F2.8 and smaller, AF mostly is accurate (I'd give the benefit of doubt to low light)
      2. F2.0 and larger, the FF is sometimes too much and at times even back.
  2. Indoor, K7 set to -7 microfocus adjustment:
    1. subject at greater than 6ft:
      1. F2.8 and smaller, again, AF seems to be very accurate (surprisingly the -7 has not done anything in this department. I really wonder how! But it's good!!)
      2. F2.0 and larger, -7 adj. seems to be a sweet spot and there is hardly any FF as aperture widens.
    2. subject at lesser than 3ft:
      1. F2.8 and smaller, again, AF is quite accurate. But does BF at times.
      2. F2.0 and larger, AF does FF as aperture widens, but a lot lesser than what it does without microfocus adj. It would wobble b/n FF and BF. I'd say it is quite acceptable, unless you are aiming at the center of a flower and sometimes it goes out of focus and the petals are sharp
  3. Surprisingly, the results for (2) holds good even if the microfocus adj. is -10, with the close subject giving a BF sometimes.

    Having found the sweetspot at -7 microfocus adj, now I headed outside with my Sigmatic Pentaxian torpedo... (someone rightly coined the verb for photography as "shooting" )
  4. Outdoor, K7 set to -7 microfocus adjustment:
    1. subject at greater than 6ft:
      1. F2.8 and smaller, as expected, AF seems to be quite accurate
      2. F2.0 and larger, AF seems to be softest at F1.4 (of course), but on underexposing, you can make out traces of sharpness. On the whole, I'd say ok with F2.0, and F1.8, but not very happy with F1.6 & F1.4.
    2. subject at lesser than 3ft (And here's the big bummer...):
      1. F2.8 and smaller, AF does FF.
      2. F2.0 and larger, AF does significant FF. If I were to focus on the center of a flower, there's no way even the petals are sharp. What's sharp is only a couple of leaves in front. Shutter speed being pretty fast (like 100 or more) and mind you, I'm a pretty steady cam holder.

In fact, no matter what I do for 4.ii.a & b, my cam just does not focus on what I want. I even tried -10 microfocus adj. Still the same. Hell, I even tried 0 microfocus adj., and no damn difference. (Call me an idiot, but just being curious, I even tried +3, or something like that, of microfocus adj. and no difference what so ever!). It almost seems to me like the newly wedded couple (K7 + 50 Sigma) have a mind of their own and make up their mind before I even make the microfocus adj!!!!!

Having said all this, no matter what I do, what the subject distance is, (with microfocus adjustment between -7 and -10), or what the aperture is, if I aim it at flesh tones (faces), I always get a sharp face! The problem is clearly visible only in my test chart testing.

[If you've read through all this to here... man you've got patience!]
So my questions to you Sigma 50 1.4 HSM owners and to other experienced photographers are:
Q1. (And this is the $500 question!): Is my lens faulty? Do I need to return it and try another "piece"?
Q2. Less significant and much as I don't mind (but for the curious person that I am) how come my K7 is behaving this way, giving almost the same results with huge microfocus adjustments???

Could the kind hearted Pentax Forums' knowledgeable souls please congregate.

<I know, I know... I will post those test pics later>

Thanks in advance. Happy shooting..

11-17-2010, 10:26 AM   #2
Raylon
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Sigma lenses have these issues sometimes. Just return it and try another one out. If it displays the same issue, it may be the K-7.
11-17-2010, 10:27 AM   #3
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With the trouble you've gone through, and the diligence you've done, I'd just swap for a new one while you can. No sense in not taking advantage of that option.
11-17-2010, 10:35 AM   #4
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QuoteOriginally posted by Rory Quote
With the trouble you've gone through, and the diligence you've done, I'd just swap for a new one while you can. No sense in not taking advantage of that option.
Very true. But I just have this thought in one corner that all Sigma 50s are this way (out of so many people facing this problem with this lens) and if so, there's no point exchanging and getting another one guaranteed to have it again.

So, what I also want to know is if anybody has a Sigma 50 1.4 HSM that is "just fine". As in, indoors, outdoors, long focus, short focus, stopped down, wide open.. even if it turned out "just fine" only after a microfocus adjustment.

11-17-2010, 10:36 AM   #5
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QuoteOriginally posted by icypepsi Quote
Very true. But I just have this thought in one corner that all Sigma 50s are this way (out of so many people facing this problem with this lens) and if so, there's no point exchanging and getting another one guaranteed to have it again.

So, what I also want to know is if anybody has a Sigma 50 1.4 HSM that is "just fine". As in, indoors, outdoors, long focus, short focus, stopped down, wide open.. even if it turned out "just fine" only after a microfocus adjustment.
Well, I know on canon forums it is praised even more than Canon's 50 1.4, so, I imagine they all have good copies. I'm sure you will get a good one.
11-17-2010, 10:52 AM   #6
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if you just keep getting bad copies (like the one you have)(btw, don't settle for something that you're not happy with), then you could ditch Sigma and get the DA* 55mm...

Just a thought anyway.
11-17-2010, 11:14 AM   #7
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QuoteOriginally posted by icypepsi Quote
Very true. But I just have this thought in one corner that all Sigma 50s are this way (out of so many people facing this problem with this lens) and if so, there's no point exchanging and getting another one guaranteed to have it again.

So, what I also want to know is if anybody has a Sigma 50 1.4 HSM that is "just fine". As in, indoors, outdoors, long focus, short focus, stopped down, wide open.. even if it turned out "just fine" only after a microfocus adjustment.
I hate to say it this way, but Sigma just seems to be "like that". When they're great, they're great, when they're not......well, it's like this lens. Frustrating. There's many people that have gone through a few copies of the 30mm before getting a good one. With the good ones, though, the sky's the limit. From what I've read, the 50mm seems to be even better.
11-17-2010, 01:16 PM   #8
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QuoteOriginally posted by Ubuntu_user Quote
if you just keep getting bad copies (like the one you have)(btw, don't settle for something that you're not happy with), then you could ditch Sigma and get the DA* 55mm...

Just a thought anyway.
You're right there about the "not happy" thing.

Btw, I looked at (or looked through!) the DA* 55 and found it about just as sharp. Very good lens. What I thought:
  • I was worried about the dreaded SDM failure that very many have reported. Even heard someone writing to Pentax for paid SDM replacement (on a dead SDM lens) with no response coming. Others say the SDM is going fine for them so far. So, my ideas about it are mixed, of course not liking to take that risk.
  • Reviews say the DA* 55 is not very accurate on AF. But I know that a Sigma 50 could have it's own flavour there :-| I have even read about the Sigma 70 200 having that curved plane of focus.
  • Alhough the Sigma 50's bokeh is smooth (something that's generally desired.. by me too), I sometimes do like the "jittery" bokeh of the DA* 55 not achievable on the Sigma.
  • I know both can go Full Frame (I was waiting on a FF from Pentax, but with the K5 so good on low light, I have to re-think)
So I might go the DA* 55 route if things don't turn fine with the Siggy.
That's reassuring, Raylon. Thanks.
I can see what you mean, Rory

I'll exchange it tomorrow and let you ppl know what happens.
Thanks everybody.


Last edited by icypepsi; 11-17-2010 at 01:21 PM.
11-17-2010, 02:59 PM   #9
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I haven't heard of the DA* AF being inaccurate, I've just heard of it being numbingly slow. It seems that the SDM problems have diminished; however, if you're uncomfortable with it, it's something to factor in. The main issues I've heard of were on the 16-50. Those seem to have subsided. It's possible they started putting the new "DC" motor in it, that more than likely is a similar set-up, just perhaps some new configuration to mitigate failures.

HSM, on the other hand, seems to get rave reviews. I wish we got the 30mm in our mount. It'd be a fun pair (50/30) to quietly play with.

Do as you plan. Swap it out with another copy. See what happens. If it's another dud, see how you feel. If it's more discomfort and disappointment, then just throw in the towel and go with a different model. Best of luck.
11-17-2010, 04:28 PM   #10
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QuoteOriginally posted by Rory Quote
I wish we got the 30mm in our mount. It'd be a fun pair (50/30) to quietly play with.
Are you talking the Sigma 30mm f/1.4? If so, that is in PK mount... At least afaik.
11-17-2010, 04:44 PM   #11
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QuoteOriginally posted by icypepsi Quote
You're right there about the "not happy" thing.

Btw, I looked at (or looked through!) the DA* 55 and found it about just as sharp. Very good lens. What I thought:
  • I was worried about the dreaded SDM failure that very many have reported. Even heard someone writing to Pentax for paid SDM replacement (on a dead SDM lens) with no response coming. Others say the SDM is going fine for them so far. So, my ideas about it are mixed, of course not liking to take that risk.
  • Reviews say the DA* 55 is not very accurate on AF. But I know that a Sigma 50 could have it's own flavour there :-| I have even read about the Sigma 70 200 having that curved plane of focus.
  • Alhough the Sigma 50's bokeh is smooth (something that's generally desired.. by me too), I sometimes do like the "jittery" bokeh of the DA* 55 not achievable on the Sigma.
  • I know both can go Full Frame (I was waiting on a FF from Pentax, but with the K5 so good on low light, I have to re-think)
So I might go the DA* 55 route if things don't turn fine with the Siggy.
I had been debating back and forth between the Sigma and DA*, both are very good lenses, and I finally decided to pull the trigger on the DA*. For me personally, I'm not too concerned about SDM--I'm an owner of a DA* 16-50 and have had no problems so far... However, the biggest consideration to me was the slower AF on the DA*, but I still decided to go for it because of a number of reasons... Some of which are-- bokeh (yes, I am pulled in by it's fascinating nature), size (both body and filter), and SMC coating (I can tell the difference, Pentax just has it figured out).
AF may be sluggish on the DA* but it's dead on accurate, according to users (I'll confirm this when I receive my copy in a few days). However, the Sigma, though fast AF, is unpredictable. You may just turn out fortunate and get a stellar copy and not have any such issues.

Anyway, I wish you well... And do let us know how this next copy turns out! My reasoning is to give a lens three tries and if the third isn't good, then defer.
11-17-2010, 04:52 PM   #12
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I had the Sigma 50 for Pentax mount and loved it. I had NO problems with FF/BF or the like...and it was sharp wide open.

I loved the lens so much that I purchased again when I switched to Nikon. The same lens (different mount this time) is again a great performer.

If you are having problems with AF I'd suggest returning it as both copies that I've had have been perfect.

As a side note...the Sigma 30 (which I had in PK mount as well) is also an awesome performer.

c[_]
11-17-2010, 06:11 PM   #13
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QuoteOriginally posted by icypepsi Quote
So, what I also want to know is if anybody has a Sigma 50 1.4 HSM that is "just fine". As in, indoors, outdoors, long focus, short focus, stopped down, wide open.. even if it turned out "just fine" only after a microfocus adjustment.
I've got one and I haven't noticed any AF issues with it; I don't pixel peep either. I love the lens. Keep in mind though, at the large apertures that the lens is capable of, the DOF is quite thin, and also, that the AF sensors aren't always exactly where the red indicator is, so there is the possibility of user error; having said that, you seem to have been quite comprehensive with your testing, and if you're not happy, I think you should send it back for a new one.

QuoteOriginally posted by Rory Quote
HSM, on the other hand, seems to get rave reviews.
I'm one that absolutely loves HSM.

QuoteOriginally posted by Raylon Quote
Well, I know on canon forums it is praised even more than Canon's 50 1.4, so, I imagine they all have good copies. I'm sure you will get a good one.
I do read POTN quite a fair bit, and while they do tend to praise the Sigma 50/1.4 over the Canon 50/1.4, focusing accuracy of the lens is an issue that comes up quite a lot, so I wouldn't say all have good copies. At least not first time around. The guys over there do like the lens, known over there as the Sigmalux, quite a lot, but only if they manage to get their hands on a good copy.

Here's their thread: Sigma 50mm f/1.4 EX DG HSM -SIGMALUX- - Canon Digital Photography Forums (you may have to sign in to see all the images)

I was open to the possibility of FF/BF issues when I got my Sigmalux, so I decided to get mine locally, so I could test the lens in store before I bought it. For what it's worth, and although I have no conclusive evidence to prove this, it seem that Sigma lenses and Canon bodies seem to have more focusing and other issues, than Sigma lenses and with other branded bodies.

Just one final thing, does the Sigmalux that you got from B&H have the new, smooth plastic finish, or the older EX finish of the Sigma lenses?
Here's a comparison of what the finishes look like: sigma_50mm_comparison | Flickr - Photo Sharing!

Last edited by pop4; 11-17-2010 at 06:32 PM.
11-17-2010, 07:11 PM   #14
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Well mine is a 11018xxx having a velvety finish. I noticed my box was old, too. Mine must have been the last of the velvet lot
11-17-2010, 09:57 PM   #15
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Hey icypepsi, I'd recommend exchanging it for another copy with B&H; they do a good job with returns.

If you're not 100% satisfied with a product, then it's worth replacing while it's free and easy. I know CRIS (the repair shop for Sigma lenses) can make focus adjustments to lenses, but I'm not sure if they can fix the issue where the lens focuses differently based on distance to subject.

Pentax and Sigma alike have ever deteriorating quality control (cutting costs in the bad market no doubt). Hopefully the number of returns (especially to the world's biggest camera store) will give them a clue that quality control isn't worth skimping. I had to exchange my K-7 twice before I got an acceptable copy...and I still have a banding issue on the sensor. Do the photography community a favor and demand perfection when you buy expensive equipment like that lens.

Last edited by jeffshaddix; 11-17-2010 at 10:03 PM.
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