rcirr Loc: Gilbert, Arizona

Thanks for the suggestion but there wasn't any. I sited a 4 Fstop over exposure because I needed to put 4 Fstop exposure compensation to get correctly exposed images.

rcirr Loc: Gilbert, Arizona

To be honest, I was hoping this was a known issue. As an electrical engineer who understands the possible issues that could cause this I would agree except that the exposure is dead on when shooting without flash. This is an interesting problem to be sure. Like I said, 4 Fstop compensation is a workaround but it will drive me nuts if I can't figure out the root cause!

rcirr Loc: Gilbert, Arizona

Same issue at 4', 11' and 25'....It's not the distance or the amount of ambient light. Thanks for the response though.

rcirr Loc: Gilbert, Arizona

Actually even though I have access to the EXIF data, I came up with the 4.2 Fstops by adding exposure compensation through the flash until I was capturing correctly exposed images. I believe you are correct in suspecting the firmware (whether reverse engineered or using licensed code to start). Since the exposure control works correctly shooting without flash AND the problem is identical using a Yongnuo flash or a Nikon flash. I think there is a firmware update needed but the website mentions a "Lens Station". I'm not sure if thats a piece of hardware or they mean the f-mount on my camera. I will try to get support to explain but I think I'm gonna be fighting language barriers. Anyway, thanks for chiming in!

rcirr Loc: Gilbert, Arizona

Sir, you are correct that neither of the flashes specifications cover 14mm. In fact neither of the flashes have settings for anything lower than 24mm. I have played with other lenses down to 12mm and while the flash wasn't designed to cover the field of view it didn't do a bad job. Further, I would think if this were the problem then the pictures would be under exposed, at least at the edges.
In regard to the camera identifying the correct itself it is. Both in live view and recorded with the pictures the data correctly identifies the lens as being 14mm.
As to the possibility of the auto exposure algorithms falling short, that makes sense. Those algorithms I assume are in the firmware so I'm going to install the latest version as soon as I get a couple of questions about the process. Time will tell. Another poster suggested the ISO setting might be the culprit. That is also a possibility I will explore. In the meantime thank you for your suggestions. I assume the mystery will be sorted out eventually and every suggestions, like Edison's failed light bulbs, brings me one step closer to solving it!

rcirr Loc: Gilbert, Arizona

The ISO is being set by the camera When I shoot manually, I have no problem. The issue only came to light because when other family members shoot my camera so I can be in the picture (without a tripod), I set it to full auto. I am starting wonder if setting the camera to auto changes some other settings as well. Thanks for the suggestion.

rcirr Loc: Gilbert, Arizona

Appreciate the suggestion. Checked them both, no compensation set. Tested again, same result of over exposure.

User ID

Its a completely manual lens. If youre not controlling the flash 100% manually then youre just creating your own problems ... or inviting your camera body and flash to create problems.

If you want wider flash coverage use a mini soft box (about $15) or bounce flash (free) or both.

The much parroted advice concerning the "inverse square law" will not apply very well. Just do a test shot and then alter your aperture and-or flash power level to get a good result.

IOW use your camera as your "studio flash meter". Its better than any hand held meter ever made. All those geeky flash meters report only numbers. Your camera does exactly the same, plus it displays a test image. No hand held meter can do THAT !

Bill_de Loc: US

I took a quick look at the flash manual. It says the flash compensation can be set by the camera or the flash. Is it possible you have one working against the other?


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rcirr Loc: Gilbert, Arizona

The problem is not in manual mode. Any manual shots I took worked fine. The problem was only when "Auto" mode was used. I believe most of the responses I received basically say the lens and camera aren't communicating well. This has been my suspicion from the beginning. I can use flash compensation when using "Auto" and it works. I was hoping for a fix (such as a firmware download) instead of a work around. The reason being that when I let someone who doesn't know how to shoot manually I might forget to set the flash compensation. Even more likely is I would forget to take it off when I start shooting other than in auto. I wouldn't see the problem until I take a look at a few shots and that is often 15 to 20 shots later.