Lens Issue

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Mike Farley
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Lens Issue

Postby Mike Farley » Sat 06 Mar 2021, 09:25

Last November I purchased the L-mount version of the Sigma 45 f/2.8 lens but have never been really happy with the results. It is does not weigh very much and has mostly stayed in my camera bag during the time I have owned it. The lens has a reputation for having a "classic" rendering and not being especially sharp wide open. I initially put my reservations down to the lens not fitting in with my style of photography and was wondering whether to sell it on. The other day I decided to give it another go and noticed that one side of a particular image lacked detail in the line of focus but something in the foreground was sharper.

That made me suspect that the lens is decentered, where one or more of the elements is out of alignment leading to inconsistent results across the frame. I did a further test shooting a newspaper with the camera perpendicular and mounted on a tripod. Sure enough, while the centre and right side of the shot were sharp wide open, the left hand side was fuzzy. I spoke to the dealer, Castle Cameras in Bournemouth, and they are arranging for the lens to be collected so that they can send it on to Sigma. The person I spoke to did mention that the problem could be the sensor not being being seated correctly, so I did a further test with a different lens which did not reveal any problems on that score. That is consistent with my experience to date using the camera. Not to mention a relief.

Ironically, when I received the lens it bore a bright yellow sticker stating it was for demonstration purposes only and not for resale. Castle Cameras claimed that they had received the lens earlier in the year but had never used it due to the shop being closed by Covid-19 restrictions. Sigma had given permission for the lens to be sold and I received a partial refund. So far as I can tell, the lens was new in the box and I could see no signs of use. It does make me wonder, though, did the lens leave the factory in that condition? Sigma most likely did not examine it before sending it out for evaluation purposes and anyone using it would probably have been disappointed.

Hopefully this story will have a good ending and I will post any relevant updates.
Regards

Mike Farley
(Visit my website and blog - www.mikefarley.net)
Mike Farley
Posts: 7210
Joined: Tue 11 Sep 2012, 16:38
Contact:

Re: Lens Issue

Postby Mike Farley » Sat 06 Mar 2021, 09:45

This is the image which raised my suspicions. Taken slightly stopped down at f/3.5, I focussed on the trunk of the central tree which is sharp at the top but soft at its base. The small bit of fern at the bottom in the foreground has unexpected detail, which should not have happened if the lens was performing properly. Other than adjusting exposure to darken the sky and lighten the trees, this is as shot and no sharpening has been applied.

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This is a crop from the lower part of the photo. It shows the trunk of the tree gradually softening and the much sharper fern.

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Regards

Mike Farley
(Visit my website and blog - www.mikefarley.net)
Mike Farley
Posts: 7210
Joined: Tue 11 Sep 2012, 16:38
Contact:

Re: Lens Issue

Postby Mike Farley » Thu 11 Mar 2021, 17:12

On Tuesday, the lens was collected by a courier arranged by Castle Cameras and the store has confirmed receipt. I now await Sigma's findings.

This latest lens is only the second one that I have owned from the company. I encountered problems with the first one as well. It had an EF mount but did not work on a Canon 300D or its successors when I upgraded to digital. Many years later, I managed to get it working again by adapting it onto a Sony A7II. I wrote more in this post:

viewtopic.php?f=2&t=2898&p=13253&hilit=sigma#p13253

Given what is quite a high price for a 45 mm lens with a modest f/2.8 aperture, albeit one which has a solid all-metal construction, I have to express some disappointment that my copy has not performed as well as I would have liked. Sigma recently introduced some new lenses into the range which get good reviews but my experience with the brand is a deterrent to making any further investment.
Regards

Mike Farley
(Visit my website and blog - www.mikefarley.net)
Mike Farley
Posts: 7210
Joined: Tue 11 Sep 2012, 16:38
Contact:

Re: Lens Issue

Postby Mike Farley » Thu 01 Apr 2021, 16:57

Mike Farley wrote:This latest lens is only the second one that I have owned from the company.

Correction. I realised that I have a third Sigma lens, a 60 f/2.8 for m43 that sold for very little money but gets good revioews. It salvages Sigma's reputation and shoots well from wide open.

Sigma has had the lens for three weeks now and has not even acknowledged receipt to the dealer. Rather than delay matters further, Castle Cameras is sending a replacement which I should receive next week. Definitely a big thumbs up for Castle Cameras, but not so good for Sigma.
Regards

Mike Farley
(Visit my website and blog - www.mikefarley.net)
Mike Farley
Posts: 7210
Joined: Tue 11 Sep 2012, 16:38
Contact:

Re: Lens Issue

Postby Mike Farley » Fri 09 Apr 2021, 19:32

Some good news. The replacement lens arrived earlier this week, a month after its predecessor was dispatched back to the dealer. I have not yet had much opportunity to take much more than a few test shots but the new lens is clearly a more capable performer.

Castle Cameras comes out of this reasonably well and have generally been helpful in resolving the various issues. Admittedly. I had to chase them after a couple of weeks and they did not follow up with Sigma as promised. I ended up making a phone call which prompted them to send me a new lens. Given that dud lenses occasionally slip through many manufacturer's quality controls, nothing has happened which would prevent me from using this dealer again.

Sigma, on the other hand, has let itself down on several counts. Not only did they release a dud lens, astonishingly it was a demo version. Their lenses come with a three year guarantee. Given their lack of response when the first lens was returned, maybe such a long period becomes more of a necessity?

One of the reasons why it took me a while to work out that my first lens was faulty were some of the reviews that I read. More than one said that it was not especially sharp wide open, the edges particularly, but improved when stopped down to f/4 and beyond. Which is kind of what I experienced, leading me to wonder whether such performance might be typical. A few reviews state that the lens is sharp wide open at f/2.8 which is more or less what I am now getting. Could it be that some of the samples Sigma put into the hands of reviewers were not well corrected?

That is potentially a problem with some reviews. Understandably, manufacturers do not like poor reports and are liable to withhold new products from someone who has written a critical article. For anyone who makes a living by writing about camera gear, it is quite an incentive not to write in anything other than glowing terms.
Regards

Mike Farley
(Visit my website and blog - www.mikefarley.net)

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