Does the EX1's computer have a separate BFocus setting for each ND position? Why is this necessary, technically speaking?

My EX1 files via ClipBrowser show ND1 even when ND is not used, is this normal? Will this affect Auto FB?

Hi, Ivan . . .

I don't know how the EX1's back flange adjustment really works. But when Sony, for instance, does work to correct a focus problem with a camera having a a removable lens they usually need to "touch up" / set up the focus for each of the ND settings. This is because a good camera has true (non electronic) glass filters. Each filter (the EX1 has two) has a different thickness. Also, each ND filter may have (like each glass element in a lens) slight imperfections that back focus adjustments attempt to correct as best as it can. This is why often doing focus adjustments for each of the ND's is useful. But whether you need to do a back focus set-up for each of the ND settings with the way the EX1 records back flange adjustment data is a very good question. I don't know if the camera has the capability to store and retain back focus data for each filter setting.

Ian

Hi Ian, thanks for your answer. Tomorrow I will run some tests regarding Auto FB and different ND filters and report here.

Hi, Ivan . . .

I don't know how the EX1's back flange adjustment really works. But when Sony, for instance, does work to correct a focus problem with a camera having a a removable lens they usually need to "touch up" / set up the focus for each of the ND settings. This is because a good camera has true (non electronic) glass filters. Each filter (the EX1 has two) has a different thickness. Also, each ND filter may have (like each glass element in a lens) slight imperfections that back focus adjustments attempt to correct as best as it can. This is why often doing focus adjustments for each of the ND's is useful. But whether you need to do a back focus set-up for each of the ND settings with the way the EX1 records back flange adjustment data is a very good question. I don't know if the camera has the capability to store and retain back focus data for each filter setting.

Ian

From the early information almost 2 years ago, I remember it was recommended to run the back flange adjustment procedure separately for all three ND settings (off, 1, and 2) - and yes, some people mentioned there's something like a look-up table for the lens to remember the setting for each. Whether this was conclusive and 100% certain - well, I'd like to know myself..

Alister?

I have had to re back focus my EX1 and EX3 from time to time. Rough handling by airline baggage handlers has upset my EX1 on a couple of occasions. I always use a flat wall with the camera perpendicular to it about 8ft away. Any type of patterned wall paper, textured wall covering or brickwork seems to work just fine.

Alister, so have you run the procedure just once, or separately for each ND switch position?

Thanks.

Hi Piotr, hi everybody and sorry for returning to this thread later than expected.

I run my backfocus adjustment with no ND filters at about 6 feet with a Siemens Star, and it didn't work, it was way off. Running the adjustment at 12 feet did it for me.

I tested my camera's backfocus with targets at 6, 12 and 18 feet away and with each ND position (OFF, 1 and 2). Everything seems to be OK. Remember I haven't run any backfocus adjustment with ND filters.

Of course, this is my case, it might not be yours. Maybe this thread bump caughts Alister's attention and he can clear this up.

I'm still afraid though, so I have sticked the Siemens Star to the back of my clapperboard. Under controlled situations I will always use it in conjunction with the peaking function, with this method I guess it's impossible to fail under simple circunstances. On the other hand, this won't easily save me if I have some zoom-in/out shots, but at least it will let me know if everything is working properly or not. I wonder how the backfocus problem affects the shot transition function's focus, any insight?

Cheers and good luck!

May the Focus be with you.

Ivan.