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09-03-2009, 08:47 AM   #1
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Sigma 70 macro trouble

I purchased a used Sigma 70mm macro from Adorama about 2 months ago. I tried using it for about a week and found it to under preform significantly. Of course user error is always a concern when I am shooting macro so consideration was taken there. But it just seemed very diffuclt to get a good sharp photo.
Also, the focusing ring seemed to act a little different than any I have ecountered. In manual mode when turning the ring clockwise it would turn almost like it was getting help from AF, spining far too freely. Counter clockwise it seemed to work properly and well dampended. Needless to say I returned the lens but I order a new one.
I am getting the same results with this lens also. Tthe focus ring has this same behavior. I have never encountered a lens with focusing this way. I would think it should turn in either direction with the same effort. I also noticed it is front focusing a fair amount also in AF and when I try to adjust with K20D which helps but I am still not getting the results I think I should with this lens.
I purchased my Sigma 70-200 around the same time so a lot of focus went into this lens and by the time I got to check out the 70 macro I was a week past the return time. So now I am going to have to send it in to Sigma corp. ( Glad I have the Lester A Dine on its way )

I guess the big question is to you Sigma 70 macro owners is what is the character of the focus ring on yours? This new one does the same thing as far as turning far too freely clockwise. I know everyone raves about this lens and I have not heard anything like this before. I keep questioning my ablilities and want to blame user error, thats why I haven't brought it up before.

Before anyone asks for picture because its hard to tell anything without, here is a set I posted on flickr and also in Post your Photos. These came out ok though I think but at a struggle. http://www.flickr.com/photos/33427578@N00/3850836962/
Any help please.


Last edited by OrenMc; 10-24-2009 at 02:56 PM.
09-03-2009, 11:26 AM   #2
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Hi OrenMc

I just checked mine a second ago.

If I'm looking through the viewfinder (just so we get clockwise and counterclockwise correct) turning it clockwise is ever so slightly more damped versus going counterclockwise on my copy (I wouldn't have ever noticed the difference if I didn't read your post and check it - it's a very subtle difference). In my mind this makes sense, as turning clockwise extends the barrel outward.

Getting a bum copy is always a possibility, but getting two bum copies (with the same concern) is pretty rare.

This is the best lens I've ever used hands down for sharpness and IQ all around (comparing to 77ltd, FA50, DA35, M50 1.7, and a couple of other sharp lenses).

In all fairness I've never used the 70 on a K20 though, however it behaves the same on both of my K10's, as well as, my K-7 so should be the same for you.

I hope this info is helpful...

c[_]
09-03-2009, 11:54 AM   #3
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Thank you for taking the time. I know sometimes we tend to pick things apart far more than needed, same as pixel peeping in which I am guilty there also. ANAL, some call it.
I never checked FF/BF issues on the first copy it just seems like a rather strange behavior with the focusing ring that I have never encountered.
You are correct in directions and I understand your explanation as to the torque. But my copies I wouldn't call slight difference, that was reason of concern. Also both copies doing the same thing. It does seem quite odd.
I am not in no big hurry to send it in, especially since my Lester just arrived. I will take a bit more time with it and try not to be so anal.

Thanks again

Last edited by OrenMc; 09-03-2009 at 02:58 PM.
09-03-2009, 01:03 PM   #4
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QuoteOriginally posted by OrenMc Quote
Thank you for taking the time. I know somethimes we tend to pick things apart far more than needed, same as pixel peeping in which I am guilty there also. ANAL, some call it.
I never checked FF/BF issues on the first copy it just seems like a rather strange behavior with the focusing ring that I have never encountered.
You are correct in directions and I understand your explanation as to the torque. But my copies I wouldn't call slight difference, that was reason of concern. Also both copies doing the same thing. It does seem quite odd.
I am not in no big hurry to send it in, especially since my Lester just arrived. I will take a bit more time with it and try not to be so anal.

Thanks again


I'm sure you know that you are covered for 90 days from receipt of an item, to return it for repair if required.

Let me know if you need any help with this.

Sincerely

Helen Oster
Adorama Camera Customer Service Ambassador


helen.oster@adoramacamera.com
Digital cameras, all other cameras and everything photographic from Adorama Camera

09-04-2009, 04:27 AM   #5
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Thank you Helen,
You are always a big help from what I have noticed.
I will PM for more information.
09-04-2009, 05:30 AM   #6
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Oren, those images on your Flickr site look quite sharp on my screen, even at original size and colours seem bold and contrasting well. I can't see you having a problem with image sharpness, but as for ease of manual focusing, each lens has a characteristic 'feel'.

My own macro the FA 100/2.8 is solidly built but does have a smooth MF focus ring movement, and can even be spun around a little with some momentum behind it.
09-04-2009, 09:07 AM   #7
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Oren,
Your pics on Flickr look pretty good to me. I own the Sigma 50/2.8 EX DG Macro and can make the following general observations:
  • My lens shares many of the same mechanical parts as yours. Focus to extend the lens (far to near) requires a little more effort that the opposite, though both directions are smooth and easy.
  • AF works very well at moderate magnifications
  • Focus point is critical due to very limited DOF at all but the narrowest apertures. What this means is that while you might get the thorax of the cranefly in focus, the head, mouth parts, and wing tips will likely be soft.
  • SR is both affective and essential when hand holding
  • While I am very happy with the lens, my impression is that I would be getting better results if I had a good macro flash setup
  • Macro is hard and requires a ton of patience
I also was tempted to add one additional bullet point, but felt that it is all too often offered as a panacea for all ills. That point is that critical manual focus is difficult with the stock screen. I have the Katz Eye which helps a lot. Unfortunately, even it has limited usefulness for macro (too much "stuff" in the viewfinder). I would love to have something similar to the finder on my KX...center microprism with ground glass donut on a bright Fresnel field.

Steve

BTW...will be curious to get your take on the Lester A. Dine vs. the Sigma 70. Both lenses have excellent reputations.

Last edited by stevebrot; 09-04-2009 at 09:14 AM.
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