I have a quick question about Ec-B screen as I just noticed that the split circle is not at the middle of the center focus point, it is actually a bit lower. I am sure that the screen is seated properly so I am wondering if this is normal? The manual focus is fine.
The center focus point is in the split portion, however, the split line is not exactly in the middle of the the itching point if the light comes up. The itching point is slightly above that line. I used the split screen quite often but this is just noticed today.
I don't understand your concern? Are you worried about auto focus accuracy within the focus square? Has this been a problem in use? If this is a substantial concern due to OOF shots with the center focus point, you could perform focus tests selecting the various focus points manually and comparing the AF position for the lens. In my experience depending upon the target, there will be a little variation in the selected focal distance over numerous determinations.
As I stated in the referenced thread the Canon manual did mention the use of center average weighted Vs evaluative for the EcB screen and I did test that and found relatively little or no difference in most targets. The manual did not (nor have other EcB users) mention AF accuracy with the EcB, so I am presuming aprioi, that there is no issue.
Mike K
I have no AF concern and certainly the focus screen has nothing to do with AF anyway as the AF module is beneath the mirror. What I am trying to figure out if this slight out of alignment between the center focus itching point and the split line is normal or not short of buying another screen and the camera, or it is my fault not seated the screen properly, even though I tried a couple times today with the same result.
Jeff, I was considering picking up this screen. I miss the center prism. Are you having any metering issues? The manual warns against using evaluative or spot metering with the Ec-B... I'd appreciate any observations you've had.
cox_ wrote:
Jeff, I was considering picking up this screen. I miss the center prism. Are you having any metering issues? The manual warns against using evaluative or spot metering with the Ec-B... I'd appreciate any observations you've had.
Michael,
I used the screen almost a year. You should avoid center spot as it will introduce most metering error. Center weighted or partial is perfectly fine. I found that the evaluative metering, even use the center focus point in most of the case is fairly accurate. The only situation I need to worry about is when there is great contrast near the center focus area such as shooting groom and bridal reception, at that time I would use off center focus point to avoid the blown up, especially if you use flash in macro shots. To further clarify, this probably still the issue of evaluative metering/ETTL II as the default screen will do the same.
Jeff, have you been following posts regarding brightscreens for the 5D? here is one from the end of one of those threads:
Here are my impressions so far.
Installation - Very simple. The first time I installed the screen the circles lined-up (concentric) perfectly. However, there were a couple of specks on the screen so I removed it to blow off the specs. I was unable to remove the specs with a bulb blower and was not comfortable with using a brush. I reinstalled the screen (specks and all) and the circles were no longer concentic. I removed and re-installed the screen several more times to try and get it positioned correctly. There is only a tiny bit of play between the screen and carrier, but enough to cause the circle to be out of alignment. After a few tries I got the screen re-installed so that the circles were perfectly concentic. It is so simple to install the screen it is not a big deal to do it a couple of times to get it aligned properly.
I used the screen almost a year. You should avoid center spot as it will introduce most metering error. Center weighted or partial is perfectly fine. I found that the evaluative metering, even use the center focus point in most of the case is fairly accurate. The only situation I need to worry about is when there is great contrast near the center focus area such as shooting groom and bridal reception, at that time I would use off center focus point to avoid the blown up, especially if you use flash in macro shots. To further clarify, this probably still the issue of evaluative metering/ETTL II as the default screen will do the same.
