Newbie - Help on Exposure (Tree VS Sky)
- Thread starter takafan
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I'm not sure about Canon, but Nikon 18-55mm kit lens has the front part rotating during focusing. Thus it's a bit irritating for CPL filter users. The very thing that you screw the filter onto is rotating, messing up your filter angle.
I do not understand how CPL Filter works.
So... meaning to say, the filter itself is not the same throughout its whole surface?
(For eg, not whole thing black. Some black some white)
Hence, if the lens rotate, it will produce different results?
Yes, my Canon lens rotates.
Im on EF-S 18-55mm IS and EF-S 55-250mm IS.
They do rotate when it Auto Focus. U hear the sound "chee chee", then it rotates, then it focuses.
So... meaning to say, the filter itself is not the same throughout its whole surface?
(For eg, not whole thing black. Some black some white)
Hence, if the lens rotate, it will produce different results?
Yes, my Canon lens rotates.
Im on EF-S 18-55mm IS and EF-S 55-250mm IS.
They do rotate when it Auto Focus. U hear the sound "chee chee", then it rotates, then it focuses.
the filter looks uniform (like a sunglass), but isn't.
If you've ever worn polarized sunglasses, you might notice differences in reflections when you tilt your head.
The exact same principle is being applied with CPL filters for camera lenses.
Having the front portion also rotate means that when you rotate the CPL filter, make sure that the focusing doesn't go off (ie subject out of focus).
You already said it yourself. It is the front barrel of your lens that rotates during focusing. This will mess up the CPL setup as the CPL achieves polarization by setting the front ring of the CPL. Lens with "internal focusing" will not rotate while focusing.
HMC just means "Hoya Multi-Coated". It is a Hoya's filter coating technology and not a filter type. All type of Hoya filters can be HMC including their CPL.
Here is an article explaining what a CPL is and how to use it.
Understood. So i should focus the shot first, then adjust the polarizer itself again, right?
Ok... So i should manual focus it first, then put on the polarizer filter, correct?
You can manually focus with the polariser attached on a bright sunny day; otherwise you'll need another pair of hands.
I'm normally switch back to my Prosumer camera when using a CPL filter because the focusing does not affect the setting of the CPL filter.
Maybe i will buy one and try first, if the 550D can auto-focus with the CPL filter.
If it can't, then i'll just have to use manual-focus
Oh wait, i think there is this circular vs linear polarizer. The circular would work with auto-focus?
Maybe i will buy one and try first, if the 550D can auto-focus with the CPL filter.
If it can't, then i'll just have to use manual-focus
All DSLR can auto focus with CPL (provided that there is enough light, which is the case here in daylight shots). I guess the term Manual Focus is a bit misleading. Focus with your camera (half-press the shutter, verify focus marks), then adjust the CPL. You don't need to hold down the shutter button during that time. Once the filter is in right position just take the picture. Make sure your focus again on the same part of the frame, use single AF point. The camera will verify the focus but this will not result in any significant rotation of the focus ring, thus the CPL settings remain.
Switching the lens into Manual Focus could even result in shifting the focus because now the AF motor and gear is decoupled from the focus ring, making it much easier to rotate the focus ring and the front element. This will happen when you turn the CPL mounted on lens front element.
It's hard to find Linear Polarizer these days. Majority of all polarizing filters are CPL.
Understood! Basically i understand the theory, but i guess its still better to hands on it myself to really understand it perfectly :thumbsup:
To sum it up, u mean:
If i auto-focus to that particular frame i want to capture, then i re-adjust the polarizer so that the effects are at its best. Then, capture the shot again in the same frame, because the focus will not move, or will not have moved much since its still roughly the same frame :thumbsup:
To sum it up, u mean:
If i auto-focus to that particular frame i want to capture, then i re-adjust the polarizer so that the effects are at its best. Then, capture the shot again in the same frame, because the focus will not move, or will not have moved much since its still roughly the same frame :thumbsup:
Saw a Phottix CPL 67mm at the PC show cost $40 at the Phottix/Eastgear booth, but i believe this is a cheapo brand and should not get it ?:dunno:
$40 is not much cheaper than a Hoya one (I think $50+), so might as well splurge a bit more...
Not sure how good Phottix filters are...
shows the power of branding eh?
you don't capture the shot AGAIN. You only capture one shot
Basically I think you shouldn't try to memorize steps. Can get quite confusing. Easier to understand the principle.
Just know that
1) The front section of your lens rotates during focusing
2) The CPL filter is screwed onto the thread at the front section
3) The CPL filter needs to be rotated to the appropriate angle to achieve the desired polarization
you don't capture the shot AGAIN. You only capture one shot
Basically I think you shouldn't try to memorize steps. Can get quite confusing. Easier to understand the principle.
Just know that
1) The front section of your lens rotates during focusing
2) The CPL filter is screwed onto the thread at the front section
3) The CPL filter needs to be rotated to the appropriate angle to achieve the desired polarization
Yup, got it. No, i dont capture the shot again. The first time just half shutter for it to focus at the frame i want to capture, then adjust the polarizer for the desirable effect, then go back to the same frame and this time capture it
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