Pentax 18-135mm mechanical vignetting near 100mm

PabloFP · 11-02-2014, 09:04 AM

Originally posted by crewl1

I'm surprised you don't have the dark corners.
Did you use closest focus with same settings?
I only see it with mine focused right up at a few inches from the target.

I would be surprised if your lens is different in design as I consider mine to be a good example otherwise.

There is a slight vigneting, but less than the bottom left corner from OP's picture, it's almost imperceptible. I would suggest OP to try composition adjustment, it seems like you have a realy bad copy.

lesmore49 · 11-02-2014, 09:12 AM

I don't know. I have an 18-135 and I've taken many a pix with it. So far, It's never been an issue...I haven't seen the issue. The lens works well, is very capable and has a useful focal range. Not a problem to me.

starjedi · 11-02-2014, 09:26 AM

Originally posted by DragonLord

As requested:

Pentax K-5 with DA 18-135mm @ 100mm. Av, 1/80s f/16 ISO 3200. Manually focused to minimum focusing distance.

—DragonLord

I took two similar shots on the screen at 100mm and F16, ISO 3200. One is 1/30s and the other is 1/80s. Do not notice any vignette. Did you put your lens hood in a right position?

**savoche** · 11-02-2014, 11:27 AM

Originally posted by DragonLord

What are your thoughts on this issue? Can you reproduce it? If so, do you find it a serious problem?

I get the same at the same settings. Mine vignettes about as much in the upper corners as yours does in the upper right, and in the lower corners as yours does in the lower left. That is without the hood, so that doesn't come into play.

Not really a practical problem for me. I have noticed some vignetting in some of my shots around 100mm, but usually I'm at 135mm if I go close to MFD. No problems with vignetting there.

Thanks for sharing, though. This issue is easy to work around once you know it's there. Just as I try to avoid 18mm; this lens (at least my copy) gets much better by zooming in just a notch.

PabloFP · 11-02-2014, 03:28 PM

Originally posted by savoche

I get the same at the same settings. Mine vignettes about as much in the upper corners as yours does in the upper right, and in the lower corners as yours does in the lower left. That is without the hood, so that doesn't come into play.

Not really a practical problem for me. I have noticed some vignetting in some of my shots around 100mm, but usually I'm at 135mm if I go close to MFD. No problems with vignetting there.

Thanks for sharing, though. This issue is easy to work around once you know it's there. Just as I try to avoid 18mm; this lens (at least my copy) gets much better by zooming in just a notch.

Yes, the difference between 18 and 21 is realy big.

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11-02-2014, 09:04 AM	#16
PabloFP Senior Member Join Date: Mar 2014 Posts: 236	Originally posted by crewl1 I'm surprised you don't have the dark corners. Did you use closest focus with same settings? I only see it with mine focused right up at a few inches from the target. I would be surprised if your lens is different in design as I consider mine to be a good example otherwise. There is a slight vigneting, but less than the bottom left corner from OP's picture, it's almost imperceptible. I would suggest OP to try composition adjustment, it seems like you have a realy bad copy.

11-02-2014, 09:12 AM	#17
lesmore49 Pentaxian Join Date: Nov 2007 Location: Western Canada Posts: 12,349	I don't know. I have an 18-135 and I've taken many a pix with it. So far, It's never been an issue...I haven't seen the issue. The lens works well, is very capable and has a useful focal range. Not a problem to me.

11-02-2014, 09:26 AM	#18
starjedi Veteran Member Join Date: Dec 2013 Location: New Jersey Posts: 932	Originally posted by DragonLord As requested: Pentax K-5 with DA 18-135mm @ 100mm. Av, 1/80s f/16 ISO 3200. Manually focused to minimum focusing distance. —DragonLord I took two similar shots on the screen at 100mm and F16, ISO 3200. One is 1/30s and the other is 1/80s. Do not notice any vignette. Did you put your lens hood in a right position?

11-02-2014, 11:27 AM	#19
savoche Master of the obvious Join Date: Jun 2011 Location: Lowlands of Norway Posts: 18,311	Originally posted by DragonLord What are your thoughts on this issue? Can you reproduce it? If so, do you find it a serious problem? I get the same at the same settings. Mine vignettes about as much in the upper corners as yours does in the upper right, and in the lower corners as yours does in the lower left. That is without the hood, so that doesn't come into play. Not really a practical problem for me. I have noticed some vignetting in some of my shots around 100mm, but usually I'm at 135mm if I go close to MFD. No problems with vignetting there. Thanks for sharing, though. This issue is easy to work around once you know it's there. Just as I try to avoid 18mm; this lens (at least my copy) gets much better by zooming in just a notch.

11-02-2014, 03:28 PM	#20
PabloFP Senior Member Join Date: Mar 2014 Posts: 236	Originally posted by savoche I get the same at the same settings. Mine vignettes about as much in the upper corners as yours does in the upper right, and in the lower corners as yours does in the lower left. That is without the hood, so that doesn't come into play. Not really a practical problem for me. I have noticed some vignetting in some of my shots around 100mm, but usually I'm at 135mm if I go close to MFD. No problems with vignetting there. Thanks for sharing, though. This issue is easy to work around once you know it's there. Just as I try to avoid 18mm; this lens (at least my copy) gets much better by zooming in just a notch. Yes, the difference between 18 and 21 is realy big.