Hi. I just picked up a circular polarizer for my 70-200mm f/4L lens,and it can be manually rotated all the way around after being fixedon the lens.Should I rotate it, or will the autofocus somehow take care of it forme.As you can see, I am quite confused..
Rotate it and look how image (especially sky and clouds) are changing when you do that. When you like what you see take a picture .
You point, zoom, focus, and then you rotate the ring until you achieve the desired result..
May I ask, what was your reason for getting it?..
I picked up the polarizer for two reasons..
1) When taking shots in bright sunlight wide open, using appature priority, my shutter speeds quite often were being set at 1/4000, which was way more then I wanted, and the camera did not like it either as it would flash the 4000 in my lcd, indicating that it was outside of acceptable ranges. I figured this polarizer would help to bring down the shutter speed to something like 1/2000 or 1/1000, which is where I would want it shooting sports outside..
2) I also figured it would be simply used to protect the lens from dirt and dust as well as acting as a polarizer...
I picked up the polarizer for two reasons..
1) When taking shots in bright sunlight wide open, using appaturepriority, my shutter speeds quite often were being set at 1/4000,which was way more then I wanted, and the camera did not like iteither as it would flash the 4000 in my lcd, indicating that it wasoutside of acceptable ranges. I figured this polarizer would help tobring down the shutter speed to something like 1/2000 or 1/1000,which is where I would want it shooting sports outside..
You usually use neutral density filters to lower the light and get long exposures in bright light..
Also I wonder why do you want to use wide aperture for your sports pictures? If you have such bright conditions set camera to Tv mode, 1/1000 sec. and let your camera handle aperture. BTW, do you use ISO100 for your sport shots? It must be extremely bright daylight to max out shutter speed at ISO100 and f/4 aperture....
2) I also figured it would be simply used to protect the lens fromdirt and dust as well as acting as a polarizer..
Hmm, CP filters are not cheap themselves. Usually UV filters are used for protection they are much cheaper than CPL filters..
Manually rotate. Sone brands put a small white line in the rim which aligns with the light source (sun) when the filter is woring to maximum effect. It is worth experimenting with the degree of shift as maximium can be too strong sometimes.Shay son of Che..
Here's a good article on polarizer use..
Although I personally find that pointing the index finger toward the sun works better. It's easier to rotate your hand and let your thumb point to all the directions of maximum effect...
Do you have to rotate a linear polarizer in the same way?..
Do you have to rotate a linear polarizer in the same way?.
Yes. There's no difference in how you use a linear vs. circular...
Also I wonder why do you want to use wide aperture for your sportspictures? If you have such bright conditions set camera to Tv mode,1/1000 sec. and let your camera handle aperture. BTW, do you useISO100 for your sport shots? It must be extremely bright daylight tomax out shutter speed at ISO100 and f/4 aperture....
I agree something does not seem right. Even with f2.8, 1/4000 sec would be 1/500 at f8 with 100 ISO. I should be so lucky with my bird and wildllife shots that require f8 for best results with the lens I am using. At 1000 mm, shallow enough DOF isn't really much of a worry to me with f8. I've never actually used it wide open (f4) except for initial testing and found it somewhat soft but 1/4000 sec as the exposure at 100 ISO just doesn't sound right to me, no matter how bright a day it is..
I may be wrong about that but the circular polarizor will give 1-1 1/2 stops difference in shutter speed and as someone else mentioned,you simply rotate it until you get the polarization effect you like. Try pointing it a partially cloudy sky and at water or a window that shows a reflection and then rotate it and you will see that you can adjust the amount of polarization between full and none.It's a great tool but not necessarily the right solution to the OP's problem..
I'm interested in seeing a sports photo (with exif data) that requires shutter speeds faster than 1/4000 to get the proper exposure and shallow DOF..
I suspect you are doing something wrong. As a beginner this is to be expected but a photo showing the problem will get you better answers than asking how to use an accessory you really should not need for sports photography with any lens. I notice you are having problems with your 85mm f 1.8. The problem is you're shooting close up objects with a wide open aperture that gives very shallow DOF except within a very narrow plane. Closer to f8 would be a better aperture to use for that but wide open may be fine for shots where the main subject is much farther away because there is less aparent depth for the camera to capture. Even then, such a fast lens is purchased for enabling the use of lower ISO in low light and narrower apertures can still give shallow DOF (dpesning on focal length and distance to subject) If this is the lens you are using for your sports, or for any lens you are using, you are (I'm assumimg) doing something wrong to require 1/4000 second at 100 ISO. Again, I may be wrong but a photo with exposure data showing the problem and some comments from others may be of more help to you than a circular polarizor will be...