[Daniel Hughes]

Hey Serg.

I have noticed this also, I think it’s the aperture though, because you can hear the little flicker.

I think it’s something either to do with the firmware or the lens you’re using.

When I use the 18-55mm kit lens it does this, but I think it’s because the maximum aperture varies with the focal length (IE you can get 5.6 maximum at 55mm, and 3.5 maximum at 18mm.)

This must mean there is some sort of mechanical relationship between the aperture and the focal length in this particular lens, which could cause flickery confusion when you zoom!

Best way to avoid this? Avoid zooming! I’m not a fan of zoom shots anyway.

Hope this helps,

Daniel

[Daniel Hughes]

Oh, I just realised you said VIDEO! Whoops.

Well it could be the same thing I guess, but the shutter in video mode is the photo diodes turning on and off, obviously not the physical shutter release, so I could only really put that down to a firmware issue (the diodes of the sensor turning on and off at slightly different times, or in a fashion where it ‘works its way up’ in a mexican wave form, as opposed to all at the exact same time. Not quite sure about that though.)

You could try to fix it with editing software, where you could split the frame into two and composite either some of the bottom half of the video, and reflect it to the top or correct the colours in the upper half until they match, but this could result in intense grain..

If you’re using 2.35:1 ratio you could even just leave out the top half of the frame completely also.

I think this problem may be similar to when you take video shots of CRT televisions, you tend to get a lot of madness and black bars.

Sorry I misread your post.

Daniel.

[Daniel Hughes]

Hi Randy.

It seems the ‘dark bar’ is just the sky you have photographed unilluminated, above more sky which is illuminated. The photograph seems to vertically represent a very short space of time.

I think it’s your shutter to be honest. If you look at the speed your shutter moves, perhaps when that area of the image was revealed to the sensor as the shutter moved out of the way, the bolt of lightening was already gone.
You take the picture and as the shutter opens, the lighting flash is under-way, but when the shutter reaches around 4/5ths open the flash of lightening is already over, so the rest of the picture will be of the same scene, but after the flash has happened. This might be the reverse of what really happened, it really depends on which way your shutter opens.

A lightening flash is generally around 1/5000th of a second, so perhaps using a longer shutter speed, in good time before and after the actual flash (perhaps use BULB) and you will capture the entire flash within the time of the shutter being completely open.

And, of course, the lightening will blast a significantly higher amount of light that the dark stormy sky before and after it, so long shutter periods should work as long as you close your aperture a bit more or decrease ISO.

I could be wrong about it, but I think this is pretty much right.

Alternatively you could become a ninja and capture it at very very fast shutter speed…

I guess you’ll have to wait for another storm to find out!
Well done for capturing this anyway, it must’ve took quite a while to get it!

Hope I’ve helped, and good luck next time!

Daniel

[Daniel Hughes]

Hi!

I am a 550d/T2i user, and I have encountered the same problem. In my current film I’m working on, one of my sets had a red door and a reddish wooden desk, with which I had grain problems even with 1000 watts of light blasted upon them.

Most of the grain problems I get are with reds, and my explanation for this is that the colour red has a smaller frequency than any other colour of light, so it has less energy than any other colour and releases the least amount of electrons when meeting the MOSFET or CMOS sensor, so the camera interprets the very low amount of electrical energy as the colour red, and because it is so low and weak it appears grainy.

I have found the best way to combat this, before you’ve even shot anything, is making sure you have the correct white balance. I never use Auto White Balance (AWB) as it never seems to work for me. If you’re using daylight, choose they daylight setting (5200K). I tend to use tungsten indoors, so I choose the tungsten setting (3200K). If you know what the colour temperature of your light is use the corresponding white balance setting. If you don’t know, a quick google with the type of lights you’re using will give you the answer, or even some trial and error taking shots with the different white balance settings. This will give you the most accurate colours and will most definitely calm down the grain.

About quicktime, the way it decodes the video does make it more grainy. My favourite way to see what my footage is more truly like is to upload to youtube and check it out the apple shop! Always looks spectacular.

You will also want to do some colour correction. Colour correction can help get the colours you actually want, and with the correct white balance, you have maximum fidelity and will be able to manage the colours more easily. If you have photo/video editing software you should be able to colour correct and manage lows, mids and highs, or you could get Magic Bullet software which is excellent for colour correction. If its a film look you’re after, once you’ve darkened it, increased contrast or applied magic bullet or whatever, grain is often greatly or completely eradicated.

I hope this helps!

Daniel