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Old Mar 23, 2008, 11:35 PM   #1
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This was taken with the sigma 105 f2.8 macro, I am not real happy with the results from this lens.
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Old Mar 23, 2008, 11:40 PM   #2
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Why?

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Old Mar 23, 2008, 11:57 PM   #3
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out of 250 plus shots I took this is the only one that is halfway decent. This lens is just to sensative for me. I would never be able to take handheld shots with it. Even tripod mounted you better have a remote as any shake of the camera takes it out of focus like right now.
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Old Mar 24, 2008, 10:34 AM   #4
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What aperture were you using? I generally use as small an aperture as I can get away with for flowers, and recently have been using a flash to keep the aperture at smaller than f11. I almost always handhold and yes - focus does become pretty critical even at f11 or f16 when you are talking about 105mm macro shots (I use the Viv Series One 105). The flash makes it possible to get good shots at that aperture without camera shake - otherwise it's hopeless for me.

Is the color correct in that picture? It looks almost like you have a strange white balance set.
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Old Mar 24, 2008, 12:45 PM   #5
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I'd like to chime in here - after a quick look at the sigma website I saw that minimal distance is 31,3cm and this gives a DOF of around 0,07cm at f=2.8...

See for yourself here: http://www.dofmaster.com/dofjs.html

Any other similar macro lense will have the same behaviour, so I can't see why you should send it back just because the lense behaves according to optical rules.

If you mostly/only go for objects that don't move, a wider lense would be better for you OR you stop down. Some numbers for a 105mm macro lense at 32cm distance compared to a 50mm macro lense at 19cm distance (i.e. Sigma 50mm macro):

- f=2.8 dof=0,07cm / 0,12cm
- f=5.6 dof=0,14cm / 0,24cm
- f=8.0 dof=0,20cm / 0,34cm
- f=11 dof=0,28cm / 0,48cm
- f=16 dof=0,40cm / 0,68cm
- f=22 dof=0,56cm / 0,96cm

The Pentax 35mm limited macro would give an even bigger DOF (13,9cm minimum focussing distance).

Hope that helps... it's really your choice or better to say it depends on what you want to photograph.

Best regards,
Th.

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Old Mar 24, 2008, 12:46 PM   #6
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mtngal wrote:
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What aperture were you using? I generally use as small an aperture as I can get away with for flowers, and recently have been using a flash to keep the aperture at smaller than f11. I almost always handhold and yes - focus does become pretty critical even at f11 or f16 when you are talking about 105mm macro shots (I use the Viv Series One 105). The flash makes it possible to get good shots at that aperture without camera shake - otherwise it's hopeless for me.

Is the color correct in that picture? It looks almost like you have a strange white balance set.
My thoughts exactly. With my Vivitar series 1 105mm lens I cannot go below f/8 or the DOF is so thin that any movement will shift the focus hand held. Very good light and a higher ISO to allow for a faster shutter speed is needed. A Macro lens has such a thin DOF that you really cannot shoot it like a normal lens...Just different technique. WB looks almost like it was set for Tungsten light.

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Old Mar 24, 2008, 12:54 PM   #7
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I did a small color balance adjustment in CS3 and got this!

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Old Mar 24, 2008, 2:58 PM   #8
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ok, I havent sent it back yet, I need to take it out tomorrow and see if I need the idiots guide to macro photography, I am not going to tell you what I did, but leave it at that.
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Old Mar 24, 2008, 4:59 PM   #9
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it looks out of focuf to me. maybe it's just camera shake. even with K10D shake reduction at this focal lenght and at this distance from subject 1/90s is too slow to have sharp image (at least for me).

try tripod and manual focus, or if you have to hand hold it use flash, at 1/180s you shouldn't have shake in photos. getting it in focus is another story


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Old Mar 25, 2008, 12:28 AM   #10
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2many wrote:
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ok, I havent sent it back yet, I need to take it out tomorrow and see if I need the idiots guide to macro photography, I am not going to tell you what I did, but leave it at that.
I won't ask and you don't tell...I bet I've done something similar at some time....What ever it was...But don't tell and I won't ask!! LOL

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