Bother with back focussing

[David Kilpatrick]

The calibration calls for losing your camera AND lens for a period - but if you called your Sony service centre/agent first, to establish a time for undertaking the work, you might be able to minimise the time in the system. The actual process takes only a few minutes, involving the camera, a test bench, a computer connection directly to the camera (very rapid with the A700 which has a hidden port for this), the lens and a few iterated tests and computer-fed adjustments. There is no dismantling involved.

David

[InTheSky]

I think after the V4.0 firmware update of the A700 to almost fix Noise at high ISO. The next update to make the A700 almost perfect could be to add the same feature as the A900 to be able to make small adjustment to the focus system. (thinking that for software dev, this should not be to hard if they already have done the job on the A900).

[Bengeo]

The next update to make the A700 almost perfect could be to add the same feature as the A900 to be able to make small adjustment to the focus system.

Perhaps it's coming ....

http://www.flickr.com/groups/sony_alpha ... 820527326/

Andy

[Javelin]

Looks like something they left out of the tech software by accident ?

[David Kilpatrick]

The Alpha 100 has only one focus adjustment register (for the calibration lens, like the 7D and 5D). It looks as if the A900 has 30 calibration registers, and they are attached to 30 assignable lens identity fields - you can calibrate any lens yourself. What we learn from this leak of v5 (if true) is that the A700 has a fixed number of calibration registers, and they are not assignable - instead, they are preset to work with a set of SAL lenses (presumably CZ as well?). And v5 will not make user addressable, it just adds an easy facility to the PC control software to change the values.

If I understand the older (v4) method correctly, adjusting the FF/BF involved mounting a lens on a test bench while the camera was attached to the PC system, and then making shots and readings which produced a correction. My guess is that the new firmware allows a manual entry of the correction, just like using the AF Micro Adjust on the A900 - but you still need the PC program, and you need the knowledge or information about the 'chosen lenses' and how to correct typical errors.

This seems to rule out the possibility of a free entry table of lens identities like the A900 has. Also, it explains some bad focus errors with independent lenses (if these happen) as some independent lenses borrow a wrong ID from the Sony/Minolta list. I gather the lens ID is two digits 00-99 and there must have been more than 99 issued lenses since 1985, so they have probably run out of lens IDs and end up re-using the most redundant ones. Of course with the A900, it only goes wrong if you own a Sigma and a Minolta which happen to share the same identity, and you need to correct focus for one of them - the other lens will then also be affected, maybe putting it out of focus.

That will not be possible with the A700 if there is a fixed list of lens corrections in the firmware. Also, it may help explain why v4 eliminated some FF/BF errors - they probably updated the entire table to fine-tune some entries which were not working out right.

David

[Javelin]

The idea of the A700 having a correction table is probably right and the A900 having a built in applet to make edits on it makes sense too. but if there is a finite number of entries in the database I don't see that as a huge problem.. who is going to have an A700 and all 99 lenses? but I guess with the 3rd party roms duplicating entries shouldn't cause huge problems if you could cancel that entry altogether and just have the camera uses it's focusing system. that way your not introducing a false error to one or the other lens and the user could get used to and compensate for the lens that has errors if it's a problem.

Seems to me that they may have good hard data for all the SAL lenses and thats why the note but this shouldn't prevent you from entering in whatever lens you have. It would be great if this and the other tech utilities were leaked. it would spawn all these groups making custom firmwares up espsecially since it looks like these use plain USB to communicate. the old sony cameras used a special LANC cable and a Russian group had made some custom stuff for diferent cameras as well as for Canon but all P&S cameras.

[David Kilpatrick]

The idea of the A700 having a correction table is probably right and the A900 having a built in applet to make edits on it makes sense too. but if there is a finite number of entries in the database I don't see that as a huge problem.. who is going to have an A700 and all 99 lenses?

All 99 lenses may apply to the A900 - but I suspect the A700 has a fixed table. It might be 16 lenses for example, fixed identities, no possibility of changing. They may have set up firmware registers which now can not be expanded because they occupy a tiny, but discrete and non-mobile, fixed address range.

David

[InTheSky]

A simple thing that can be very good for firmware upgrade too, is to simply add a field inside our camera to fill the creator field of the EXIF ...

I don't know why this simple thing it this hard for software developer to had. I remember having this option in my old Canon point and shot camera.

Regards,

Frank

[stroberaver]

Woooh, that firmware would be superb. Would save me having to send off my camera & lenses, which I'm not at all looking forward to.

I had a look on sony's site for support information about sending my camera back whilst I'm waiting for a chance (i.e. daylight) to take those wide angle shots with the centre sensor - nngh, what a nightmare. Going round in circles, useless stating-the-obvious advice - anything but a simple email or phone number for UK service of Sony Alphas! Does anyone know if they have regional centres, or is it one place for the UK? The only option I can find is to submit a "service request" which seems to entail entering more information than buying car insurance! Anyone know where I can find some simple contact information of service centre(s)?

[David Kilpatrick]

Woooh, that firmware would be superb. Would save me having to send off my camera & lenses, which I'm not at all looking forward to.

I had a look on sony's site for support information about sending my camera back whilst I'm waiting for a chance (i.e. daylight) to take those wide angle shots with the centre sensor - nngh, what a nightmare. Going round in circles, useless stating-the-obvious advice - anything but a simple email or phone number for UK service of Sony Alphas! Does anyone know if they have regional centres, or is it one place for the UK? The only option I can find is to submit a "service request" which seems to entail entering more information than buying car insurance! Anyone know where I can find some simple contact information of service centre(s)?

Try Photoclubalpha!

http://www.photoclubalpha.com/useful-an ... formation/" onclick="window.open(this.href);return false;

We also publish this and other links in every single magazine issue, along with an independent service shop for older gear.

David

[bakubo]

Perhaps it's coming ....

http://www.flickr.com/groups/sony_alpha ... 820527326/

There is new update at the bottom of that page that says that this v5 fw has slots for 5 lenses and may get released in March plus some other changes. Of course, none of this may be true, but it might.

[Jonathan K]

Hi all,

since we are talking focussing issues again (and a potential solution to them):
The many posts here have made me believe that a lot of the 50/1.4 focus issues are (at least partly) due to focus shift. Since I use the Sigma 50/1.4, I also experience that in practice and it seems as if my A700 body is not that badly calibrated after all...

except:

The only other lens that does not work is the Macro 100/2.8. For macro photography it works, focussing seems fine (I didn't do any real "testing", just judging the results I get when use it), but between 4 an 7 meters distance the focus is way off... about 20-25 cm.

I own the second version of the Minolta 100/2.8 Macro. Is there any reason why this could be? Why should it be the only lens that does not work? Beercan or 100-300APO work fine at 100mm.
Since the center AF sensor is sensitive up to f2.8, there should be no reason for focus errors...

Does anybody else experience this?

Thanks in advance,

Jonathan

[lock]

Also worth mentioning is that with my 70-300G, the focus accuracy seems better towards 300mm. The telezoom samples posted previously were all at 70mm. Any advice is most welcome on how I go about getting my telezoom focus @ 70mm to work properly.

My 70200g shows a similar behaviour. Strong BF at 70 mm, more or less normal around 135 mm, but a tendency to FF at 200 mm. Get this V5 going !

lock

[stroberaver]

Woooh, that firmware would be superb. Would save me having to send off my camera & lenses, which I'm not at all looking forward to.

I had a look on sony's site for support information about sending my camera back whilst I'm waiting for a chance (i.e. daylight) to take those wide angle shots with the centre sensor - nngh, what a nightmare. Going round in circles, useless stating-the-obvious advice - anything but a simple email or phone number for UK service of Sony Alphas! Does anyone know if they have regional centres, or is it one place for the UK? The only option I can find is to submit a "service request" which seems to entail entering more information than buying car insurance! Anyone know where I can find some simple contact information of service centre(s)?

Try Photoclubalpha!

http://www.photoclubalpha.com/useful-an ... formation/" onclick="window.open(this.href);return false;

We also publish this and other links in every single magazine issue, along with an independent service shop for older gear.

David

D'oh! I'm a subscriber, too - forgot about the page of useful links and numbers inside each front cover. Thanks for the number.

I just wish Sony would say something about these v5 rumours. I need my camera for some kids birthday parties and events at my camera club, but I also want it to focus accurately!

[Brad Smith]

Hi strobeweaver,

My A300 back focused with all 3 of my lenses as soon as I got it but I fixed it myself and you can too if you're feeling a little brave.
It's a fair bit to type up but if you want to give it a go let me know and I'll post how to do it.

Brad