canon 500D 50mm F1.8 lens stopping down to F2.8 in live view unless I hold aperture preview?

[realflow100]

Why does it do this in live view mode?
it makes live view darker and harder to see unless i constantly hold down the aperture preview button when in low light

my lens is yongnuo brand II

[realflow100]

Am I doing something dumb? Did I mess something up? or is this the normal behavior?
Why would it want to stop the lens down to F2.8 in live view mode?

[Baurice]

I don't know if anyone here has the same camera and lens as you do. I do lots of DSLR photography but don't use live view. I have a Nikon D3200.

[JayTee]

Point your camera at the Moon. Manually select ISO 6400. Manually select f/1.8. Manually select 30 second exposure. Press the exposure button halfway down, this should lock in those values. Now select liveview and see what happens.

[realflow100]

Nope. it doesnt matter if im indoors. well lit room. dimly lit. or pitch black. it always does this no matter what. unless I use exposure override with magic lantern. which is annoying to do every time!

And omg this lens is so bright it absolutely blows my other lenses out of the water in low light
It actually can see things better than my eyes in real time!
theres very little noise too.

[realflow100]

I posted a video showing real time just how bad the light pollution is where im at. (The moon isn't even affecting it!)


You can make out the big dipper and some bright constellations. but not very easily.

The trees look like they are on FIRE

[Graeme1858]

Hello Realflow

I haven't used an SLR with a lens on for a while! From memory, is it not the case that live view displays with the camera lens at maximum aperture (F1.8) to give the brightest view and then with a half push on the shutter release button it will stop down to your chosen aperture setting to show depth of focus and so darken the live view image?

I'm sure this is how it has worked on my cameras through the viewfinder.

Regards

Graeme

[realflow100]

Nope. only on my other lenses does it do that.

On this lens it always stops down to F2.8 for some reason in LIVE VIEW mode.
in video mode it will go wide open aperture if its dark enough. so its just normal live view mode doing that for some reason and i cant figure it out

only way around is holding the preview button while set to F1.8 so it will go wide open and a bit brighter.
or use magic lantern exposure override and manual mode to make it wide open.

Maybe my camera just wasn't designed to work well at F1.8 in live view for some reason and it wants to limit it to F2.8 for the focusing mechanism or something?

[John Baars]

I am not an expert on Canon.
Somewhat older camera's crop when a video is taken on 4K. That could be the answer.

[realflow100]

I'm not doing video though. and my camera does not take 4k video either. only 20FPS 1080p.

I'm doing NORMAL LIVE VIEW. my camera is already APSC/crop.

I dont see how changing the aperture is related to cropping

I dont seem to have this issue in video mode. its wide open properly when it should be.

I find when stopped down a ways. like F8 or smaller the aperture blades dont make a perfectly round hole. seems wonky and not perfectly circular. also seems to not always make the same shape when stopping down. its a lumpy aperture when stopped down a lot.

[realflow100]

Nevermind the lens died. communication errors all the time and it barely works suddenly
Time for a refund what a bummer

I guess i'm going to try to save up and get the canon 50 1.8 STM instead