Can't stop down below f4.0 on 5DMIV

[Roger1019]

I was testing my new Sigma 24mm f1.4 yesterday and realized that I could not stop it down below 4.0. So I mounted my (also new) 50 1.4: same thing. Then I got out my 100 2.8 macro and found I couldn't stop that down either. Went through all the menus, reset everything to default with no change. I then flashed it with the latest firmware. No luck there either. Then I put the 50 on my 5DMII. Worked fine. Same with the 24. 

Next I Googled the problem, but could find no mention of this anywhere. And finally, I searched Lightroom for any image taken with the MIV with an aperture below 4.0. Not a one. As expected, lots of photos taken at 4.0, but that's because none of my zooms go below 4.0. And I doubt if I've attempted to shoot much of anything below f8 with the 100, but no surprise there.

Anyone ever hear of something like this? I keep feeling like I'm missing something obvious. I'm hoping it's not a bad main circuit board....

Help!

[Waddizzle]

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@Roger1019 wrote:

I was testing my new Sigma 24mm f1.4 yesterday and realized that I could not stop it down below 4.0. So I mounted my (also new) 50 1.4: same thing. Then I got out my 100 2.8 macro and found I couldn't stop that down either. Went through all the menus, reset everything to default with no change. I then flashed it with the latest firmware. No luck there either. Then I put the 50 on my 5DMII. Worked fine. Same with the 24. 

Next I Googled the problem, but could find no mention of this anywhere. And finally, I searched Lightroom for any image taken with the MIV with an aperture below 4.0. Not a one. As expected, lots of photos taken at 4.0, but that's because none of my zooms go below 4.0. And I doubt if I've attempted to shoot much of anything below f8 with the 100, but no surprise there.

Anyone ever hear of something like this? I keep feeling like I'm missing something obvious. I'm hoping it's not a bad main circuit board....

Help!

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What shooting mode(s) are you using?  

It sounds like the “Safety Shift” feature is kicking.  It is active in Tv and Av modes.  I would have thought that activating the main menu “Reset To Factory Defaults” should reset that feature, too.  Maybe not.

[HINT]. The menus can be slow to navigate from one group of settings to the next group.  Next time, press the [Q] button.

[Anonymous · Accepted solution]

In the custom functions menu #2 there is a Set Aperture Range where you can limit the min and max aperture setting. See page 488 in the manual.

[Roger1019]

That was it. And here's what's weird. I saw that menu as I was going through everything, and I did notice it was set to 4.0. I changed to 1.4, pressed the Set button, and exited. Didn't work. 

After I saw your suggestion, I returned to the Set Aperture Range and, voila, it was back at 4.0. So this time, instead of pressing the Set button, I tapped the handy OK button on the screen. 

And it worked. My camera's 'fixed'. Thanks much for your help. I do have to admit that I'm a little surprised the Set button didn't work in this case. Is there a reason for this? I haven't run into it before.

Anyway, thanks again.

[Anonymous]

The manual says to select OK, so i guess that is the explanation. Glad it worked out.

[BurnUnit]

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@Roger1019 wrote:

...I do have to admit that I'm a little surprised the Set button didn't work in this case. Is there a reason for this? I haven't run into it before.

Anyway, thanks again.

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I think that from a given menu screen you can select and "set" multiple camera adjustments. After you're done going thru the list making these settings you then have to click "OK" to actually apply any of the changes you've made. It acts like many of the settings screens you find in Windows.