DPReview.com is closing April 10th - Find out more

Effective aperture

Started May 25, 2020 | Questions thread
ForumParentFirstPrevious
Flat view
Stuart Carlton Regular Member • Posts: 203
Effective aperture

I have a Sigma 150mm f2.8 macro lens, the later OS version, and while I am very pleased with the results have been troubled by underexposed images.  When taking close ups of insects I usually have to compensate by up to 2 stops. I thought this was a lens problem so had been in discussion with Sigma about firmware upgrades.  Despite initially saying no upgrade was available recently they have said they have such an upgrade for this lens when coupled to a Canon 7D2, which is my goto camera for macro.

Recently, however, I noticed that this effect disappeared if photographing subjects further away and I have now been introduced to the concept of effective aperture which I had not appreciated previously as I don't think my Canon 100mm macro exhibits this effect, at least not so obviously.

My question is, therefore, if this is a case of the effective aperture resulting in underexposure can a firmware upgrade reduce the effect?  Intuitively it seems to me not but I would be grateful to hear any views and if others have experienced this effect with this lens.

ANSWER:
This question has not been answered yet.
ForumParentFirstPrevious
Flat view
ForumParentFirstPrevious
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow