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5DsR exposure simulation issue


Hi all, I've bought a 5DsR and I'm having issues with ExpSim while shooting in M in dark scenes.


Sometimes I cannon even get a preview at 0ev because ExpSim alert kicks in way before that. Both Live View and the istogram stop reacting more or less when the smallest part of the scene gets blown out, so I cannot see what I'm doing when deliberately overexpose for taking a pic of the foreground at sunset, for example. My other camera, an Eos R, can go all the way up to 30s blowing out almost everything at will. ExpSim is on for both cameras, and I've tested using the same lens which is a 16-35 f4L. Is it normal for the camera? Is there something I can do?


Not to mention that I cannot use contactless lenses like a Samyang 14mm with ExpSim, which is working correctly on the R...


Thank you,



Product Expert
Product Expert

Hi there,


There are two potential causes taht come to mind. The first is the safety shift function in your custom functions settings, you will want to make sure it is not enabled. And the second is to make sure you are not shooting in Auto ISO since this could cause the LCD screen to try correcting back from your selected exposure. If the Auto ISO is causing the issue you will also be able to tell by adjusting the exposure compnce on the LCD screenensation and seeing the difference immediately.

In addition I would reset the camera and start all over.

EOS 1DX and 1D Mk IV and several lenses!


An EOS 5DS or EOS 5DS R will exhibit exposure simulation failure at any EV less than 2. This is normal behavior. As you note, the EOS R has a significantly lower limit as it can continue exposure simulation all the way down to -4 EV, six stops lower. That is also normal. Sorry, but I am unaware of a technical workaround for your EOS 5DS R, as I am assuming you want to use a live histogram at an EV lower than 2.

Thank you for the replies