I've been shooting Pentax for a few years and feel that my k-5, although slow, would lock in low light situation like these. AF mode was single shot with expanded center focus point. all 9 center focus points.
With a shutter speed of 1/5000, the shutter curtains move in tandem, with only a slit open at any point in the image. Based on the width of that underexposed band and the tapering of its tone at the edges it almost looks like the curtains skipped over the center of the image too quickly. Does it only happen at fast shutter speeds? Is the underexposed band always in the center?
if ninjas do start jumping out at me in the dark, i want to make sure my camera can take their picture.
Half his face is lit. it should have locked on the left side of his face.
when i first encountered the issue, i thought it was the shutter speed too but that doesnt matter. I think it has something to due to bright white objects. here are three examples from when i was at the zoo. these were taken out doors at night.
Those additional samples are also at shutter speeds above x-synch (meaning there will be a slitted shutter exposure) and all have a dark band that is parallel to the shutter curtains. Looks like a shutter issue to me.
It's AC voltage flicker in the first shot, due to using a high shutter speed. It's chance. Probably fluorescent or some variety of indoor mercury vapour lights.
The first photo almost certainly has illumination from several lights which are out of sync so that their cycles mostly overlap, but you caught a dip in one shot.
The LED penguins are being run off one circuit and being cycled in sync. Hence large swaths are off for part of the shot.
People talking about x-sync (flash photography): there is no evidence in the photos of flash having any effect, even if flash is enabled and connected (OP?) The LED penguins are lit by the LED with no ambient lighting.
It seems nonsensical to say flash, because flash problems would show up as a tiny slit way on one side and all the rest black, especially tiny at 1/5000 second.
Note how the penguins at 1/2500 has more illuminated than the 1/800 shot. You'd expect the opposite for flash.
Jorge, why are you using such high shutter speeds and such wide apertures? It seems completely unnecessary and counter-productive in your situation. There seems to be no call for shallow depth of field in those pictures.
The first one at ISO 10,000, f/1.2, 1/5000 sec would probably be better shot at f/5.6 1/250.
What reasoning did you use to choose the exposure settings in your photos?
I think the camera is fine and the problem is operator error, sorry to have to say it. However if our positions were reversed, I'd be glad for the opportunity to learn about technique, so see this as a chance to figure some things out and get better.
Monito wrote:
It's AC voltage flicker in the first shot, due to using a high shutter speed. It's chance. Probably fluorescent or some variety of indoor mercury vapour lights.
The first photo almost certainly has illumination from several lights which are out of sync so that their cycles mostly overlap, but you caught a dip in one shot.
The LED penguins are being run off one circuit and being cycled in sync. Hence large swaths are off for part of the shot.
That's what I'm trying to get across, but I don't think the OP is listening. A tripod and a slow shutter speed would be better.
Monito wrote:
People talking about x-sync (flash photography): there is no evidence in the photos of flash having any effect, even if flash is enabled and connected (OP?) The LED penguins are lit by the LED with no ambient lighting.
It seems nonsensical to say flash, because flash problems would show up as a tiny slit way on one side and all the rest black, especially tiny at 1/5000 second.
Note how the penguins at 1/2500 has more illuminated than the 1/800 shot. You'd expect the opposite for flash.
The OP never said anything about using flash.
Nobody said anything about flash. Besides x-synch being the speed relevant for flash exposures, it also defines the speed at which the shutter curtains move I'm tandem for a rolling exposure, which can create the slit effect when the curtains aren't moving at a constant or correct velocity.
EB-1 wrote:
That's what I'm trying to get across, but I don't think the OP is listening. A tripod and a slow shutter speed would be better.
EBH
If the dark band was the result of cycling LEDs then the orientation of the band wouldn't follow the orientation of the shutter curtains between the photos taken at landscape vs portrait.
I think we are seeing the interference of the light cycling and the portion of the slit open (a movement across the short dimension of the frame). If there were a mechanical problem with the shutter it would not occur at different places in different shots.
i was just surprised as i have never encountered this. i have been shooting for a few years now, pentax kx, 2 k5s, sony rx100, various 35mm and medium format cameras and have never seen this happen. as to why i chose the settings i did was simply to play with iso 10000+ and f 1.2. i just wanted to see how the camera and myself handled the high iso and dof. i know 1.2 is hard to achieve focus with so i try to shot at 1.2 as often as possible just to practice. ive only had the camera and lens just a few weeks.
I don't know what is causing the problem with the dark area, but you have made strange choices with the settings. Surely you'd be better to reduce ISO, lower your shutter speed and close down your lens a bit...?
I'd only shoot at ISO 10,000 for extreme night-time situations, and even then reluctantly.
EB-1 wrote:
I think we are seeing the interference of the light cycling and the portion of the slit open (a movement across the short dimension of the frame). If there were a mechanical problem with the shutter it would not occur at different places in different shots.
EBH
I'm thinking the shutter curtains are cycling at inconsistent speeds, and if so could happen at any point of the exposure. Notice how the width of the dark band varies with shutter speed, roughly matching the expected size of the shutter slit at that speed.
