Having issues with 7D.

B

bobafet1

Active member
I'm still learning how to use my 7D so forgive me if this is rookie stuff. I bought the 7D with the standard 18-135mm lens and when I zoom in or out when recording video the brightness either increases or decreases real quick. I don't know if it is the lens causing the issue or a setting.. Either way, I need to figure this problem out fast since it is ruining my shots.

Any help is appreciated.

Thanks,

Mike
 
The lens doesn't have a fixed aperture. It changes from 3.5 to 5.6 when you zoom in. That is why the brightness decreases. If you want to work around that, set the aperture to 5.6 from the start, than you won't notice anything.

Happy shooting!
Fx
 
If you're shooting video indoors you will find the 3.5-5.6 too slow for many applications. You will want a lens that's 2.8 or faster for good low light performance.
 
NoahK said:
Yup- I'd suggest the 50mm 1.8 as your next lens... :)

Noah
Click to expand...

A good recomendation however, I would suggest a few more dollars and get the 1.4 because of form factor. The 1.8 is a great lens for the money however, the focusing ring is less than a 1/4 of an inch. The 1.4 has a very nice focusing ring and is more practical for a video application. ehh... just me 2 cents
 
ok, so this really comes down to the lens. Drats!

Time to start saving up some freakin cash...

thanks everyone for the info.
 
FixMix said:
The lens doesn't have a fixed aperture. It changes from 3.5 to 5.6 when you zoom in. That is why the brightness decreases. If you want to work around that, set the aperture to 5.6 from the start, than you won't notice anything.

Happy shooting!
Fx
Click to expand...

You can do this and use it as a variable prime.
For example, shoot at 35mm/f5.6 and cut to 85mm/f5.6 and exposure will be the same.

However – you cannot leave the aperture on 5.6 and record while zooming from wide to tele
as you will see a flicker at the points where max aperture changes and the flicker will be recorded.

If you want to record a zooming shot you will need a fixed aperture zoom like 17-55/2.8 and then the best way is to attach a follow
focus to the zoom ring so you can precisely control the zoom. Even with this control results are patchy. To do a zoom shot properly you need
a cine zoom and they cost truckloads of money.
 
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i borrowed my friends 50 1.8 until i got my nikon adapter and i would agree with NC17z comments. I attempted to attach a lens gear to the focus ring and it does not accept them willingly. i'm sure you could rig up something for it but the 1.4 would definitely be a better choice.

Don't forget about older manual lenses if you're on a budget, tons of great options available.
 
J Davis said:
You can do this and use it as a variable prime.
For example, shoot at 35mm/f5.6 and cut to 85mm/f5.6 and exposure will be the same.

However – you cannot leave the aperture on 5.6 and record while zooming from wide to tele
as you will see a flicker at the points where max aperture changes and the flicker will be recorded.

If you want to record a zooming shot you will need a fixed aperture zoom like 17-55/2.8 and then the best way is to attach a follow
focus to the zoom ring so you can precisely control the zoom. Even with this control results are patchy. To do a zoom shot properly you need
a cine zoom and they cost truckloads of money.
Click to expand...

I noticed the brightness change today... I shot at iso 100 outside and set my aperture at f10, when I zoomed in, I noticed the brightness go up (I can also hear the camera servo) and then back down when I zoomed out... There's no way around this when using a 3.5 to 5.6 zoom lens? The brightness is always going to change when zooming in? I'm using the 28mm to 135mm kit lens...
 
azboy1985 said:
There's no way around this when using a 3.5 to 5.6 zoom lens?.
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That's what the variable aperture is telling you, and why experienced shooters don't use them, and tell you guys not to buy them either. Everyone wants to learn the hard way.

To work around this set the lens aperture to 5.6 manually, then it wont change when zooming.

Why are you zooming anyway?
 
PerroneFord said:
That's what the variable aperture is telling you, and why experienced shooters don't use them, and tell you guys not to buy them either. Everyone wants to learn the hard way.

To work around this set the lens aperture to 5.6 manually, then it wont change when zooming.

Why are you zooming anyway?
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I did set my aperture to 5.6 and 10 and both times, while the aperture did not change on screen while zooming in... I can hear the servo working and the screen brightens up when zooming in... From what I'm reading, this shouldn't be happening, correct? If I set the aperture to 5.6 and then zoom in, the picture should not brighten up or flicker in any way...

I was zooming on test footage to see if the flicker does happen with my kit lens while using 5.6 and up aperture settings... I understand that the aperture will change if you start at 3.5 and then zoom in... it changes to 5.6... But I'm starting at 5.6 or in my previous post at 10 and then zooming in and I notice the image flicker and the brightness goes up. Should it be doing that?
 
PerroneFord said:
To work around this set the lens aperture to 5.6 manually, then it wont change when zooming.
Click to expand...

This is good in theory but it doesn't work in practice.


azboy1985 said:
Should it be doing that?
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Yes this is correct and normal as I stated in my earlier post.



If you set a 3.5-5.6 aperture zoom to 5.6 at its widest and zoom for the full length of its range at 5.6 all the way you will see an exposure change in the form of a flicker at every focal length where there is a designated 'widest aperture jump' and this flicker will be recorded.

You can also stop at a camera store, borrow a lens and test it for yourself.

This doesn't mean the lens is useless. Use it as a variable prime.
 
Actually, on this note of using a variable aperture zoom as a variable prime.
The 18-55mm / f3.5-5.6 is a very good starting out lens for independent film makers.

New it can be bought for $140, as a kit lens with the t2i it is $100 and there are plenty of people selling them on craigslist in
brand new condition for even less.

Its useful because sharpness tests place it better than the 28-105 (var. aperture) and the 28-135 IS (7d kit), when tested at 28mm, 35mm and 50mm.
Also it covers 24mm which the other two don't.

So you have three prime focal lengths that are often used in film making (24mm, 35mm, 50mm) all with more than decent quality and a perfectly
workable f5.6 aperture on all three lengths and all in the one lens. The zoom is built for 18-55 so if you stay at 24, 35 and 50 you are never shooting at
its widest (avoiding barrel distorion) or longest (avoiding pincushion effect).

Image Stabilization for hand held shots as well.
 
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@J Davis: I have the 18-55 Canon but not the IS version (I have the AF one). How does it compare? Do you know if that performs the same in terms of IQ?
 
J Davis said:
This is good in theory but it doesn't work in practice.
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I do NOT remember this happening on my old zooms, but there was no computer in them or my cameras. Is this a function of the new technology? Or is my memory just faulty. It has been a while...
 
Ian-T said:
@J Davis: I have the 18-55 Canon but not the IS version (I have the AF one). How does it compare? Do you know if that performs the same in terms of IQ?
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I don't own both but I use this site for comparisons
(roll over/roll off, watch little white arrow)
18-55 non IS (30D) vs 18-55 IS (40D) LINK (the IS version looks better IMO)
and for the earlier post
28-135 f3.5-5.6 vs 18-55 f3.5-5.6 LINK

PerroneFord said:
I do NOT remember this happening on my old zooms, but there was no computer in them or my cameras. Is this a function of the new technology? Or is my memory just faulty. It has been a while...
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How old is an old? Canon Manuals? FD's? older EOS zooms?
BTW - I love old lenses, especially my AIS primes and zooms,
my 75-150/3.5 and tomorrow I am picking up a rare 50-135/3.5 in mint
I have a FD cosina with the craziest flares (LINK) and a FD 24/1.4L which I love

but as for the modern lenses ...
I have personally seen the 18-55 IS (t2i kit) and 28-135 IS (7d kit) both flicker across the zoom range.

edit: once again to others coming in late, this flicker doesn't meant the lens is useless, use the lens as a variable prime, see my earlier post
 
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J Davis said:
I
How old is an old? Canon Manuals? FD's? older EOS zooms?
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Well I started on a rangefinder if that tells you anything. But I had zooms on my AE1, T70, !0s, and F4. In terms of old glass I am referring to FD and AI and pre-AI F mount glass.
 
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