Couple of EOS 3 questions

<p>Firstly, is there any way to check which firmware I have? I know from the date code and serial number I have an early model from 1998. I know some early models had an underexposure issue under certain circumstances and although I've not noticed this I would like to check the firmware.</p>

<p>Secondly, I was trying to check out the cross-type AF points tonight using my EF50 1.8 and my EF24-105L. From reading the manual I would have expected the EF50 to be utilising the 7 central AF points and the EF24-105L to be using just the centre AF point but I couldn't get either lens to focus on vertical lines in dim light. Horizontal lines were fine. This suggests that cross-type AF points were not active. Any ideas?<br>

Thanks in advance.</p>

<p>http://www.photo.net/canon-eos-digital-camera-forum/004twz should tell about the firmware upgrade<br>

From the canon.co.uk website:<br>

The EOS 3’s ground-breaking area AF system uses 45 focusing points for accurate subject capture. The seven focusing points at the centre are high precision cross type sensors for f2.8 lenses, or faster, while the other 38 are sensitive to horizontal lines at f/5.6. Even with an f/4 or faster lens, the centre focusing point works as a cross type focusing sensor, greatly enhancing the prospect of capturing the desired subject.<br>

I hope this helps.<br>

Henry</p>

Only the center AF sensor will operate as a cross sensor with an F4 lens like the 24-105. With a variable aperture zoom that has a maximum aperture in excess of F4, the EOS 3 will have no operational cross sensors. While the 50 f1.8 will have 7 cross sensors active, it is one of the poorest low light AF performing lenses I have ever owned, and it is not surprising it failed for you in low light.

I would recommend using custom settings to expand the focus points around the focus point that is set, to give the AF system a bit of help in low light with slow lenses. Not sure how you can check firmware, but you will need to send it to Canon for an update (no USB ports or CF cards on an EOS 3!)

<p>Thank you both for your help. I am aware of what sensors should act as cross type and with which lenses. The problem is that they don't seem to be working on my body. All 45 sensors are working fine as vertical sensors, i.e. they all lock happily onto horizontal lines. However, after further experiments, I have found that only one of the seven cross type sensors (and not the centre one) will achieve a lock on a vertical line. I obviously have a problem and I now have to try and figure out what is wrong and decide if the cost of repair is worth it in relation to the value of the body. I suppose if focusing is critical I can always focus/recompose using the good sensor.</p>