Z7U lens / camera issue - Need help
 

Those who can take a few mins. to do a simple focus test with their Z7U, would be greatly appreciated.

I have been having ongoing problems with several Sony Z7U camcorders, and I'm at the end of my tether with Sony for a) the length of time trying to problem solve and b) not matching the camera and the lens acceptably. There are definate problems affecting many Z7U's with the stock lens with focus and back focus issues.

I am meeting with Sony next Wednesday about Z7U issues and would like to show them one problem that might be helpful in terms of probelm solving some focus issues.

If a couple of folks such as Greg Laves or other regurlar contributors could do the following - it would be helpful:

When doing the following, what distance reading (in feet on your Z7U LCD panel) do you get from an object approx. 20’ from camera? Use a measuring tape to get the true distance. And when focusing the camera, keep an eye on the distance display (LCD). Please let me know what discrepancy there is between the true distance (measured by tape to object), and what the camera reports in feet on the LCD. I used the front to the lens (not lens hood or where the sensor might be) as to where measurement was taken from.

Currently I have two Z7U's. What is a concern is that both cameras at 21’4” from object or chart (true distance, measured with measuring tape) is reported by one camera as being 24’ from camera (when in perfect focus, using monitor) – while the other reports being 25’ away. Being more than 2.5 feet and 3.5 feet off when doing mechanical measuring is a lot.

With other small and larger format cameras, I've been able to measure distance using a measuring tape and get great results. I can't with the Z7U, since the camera isn't able to handle accurate (or even closely accurate) measurements and get focus right.

If anyone wishes to PM me with any info. that would be great.

I'd love to hear from a few of you before meeting with Sony folks on Wednesday.

Thanks.

Ian

Back focus?

Yes, there does seem to be a back focus problem with some units - some worse than others. Peter Ford (see thread below) has what looks like an extreme example of what this camera can look like. We've done the back-flange adjustments to no avail (both manual and auto) many times before going to Sony for help. After almost a year, they have been able to finally provide support. Even when the cameras get the focus RIGHT, the distance the LCD (feet or meters) reports as the distance you've focused to, gets it wrong. I think this anomaly may be a part of the problem with the model -- so I'm hoping others can do the distance / focus test and let me know the results.

Sony has recently tweaked one of our cameras -- and now it looks great. The problem now, however, is that we want to buy the $2,500.00 wide angle Sony Ziess lens -- but it looks "soft" according to the test Sony did with the wide angle on the "tweaked" camera. It's not a great match.

Ian

Ian, it has been a while since I did it and I don't remember all of the details. I did have to use the manual adjust flange back mode since it continually failed at auto flange back adjustment. And I do remember that I set my backfocus adjustment chart at exactly 10 feet and then did the manual adjustment steps. When I was finished, the lens also said 10 feet on the lens gauge. While I have not measured the exact distances at other ranges (like 20+ feet that you were measuring) it did seem to be pretty accurate from what I would estimate. But my eyeball calibration could be off. I have a Fujinon lens on the camera right now. When I get a chance, I will install the std lens and do some testing to see how accurate it is at other distances.

Thanks Greg. I appreciate your input. I hope to have a little more info. tomorrow from Sony about the Stock lens and camera body mismatch. The problems some have are between the electronic stock lens and / or the accessory Zeiss lens made specifically for the Z7U. The use of a true broadcast lens like a Funjinon work without a hitch with the Z7U due to the manual nature of being able to control the back element of the glass direcly with the adjustment lever.

After Sony set up "tweaked" one of our cameras that had a bad back-focus problem, it drew our attention to how poorly performing our other good (or so we thought) camera was by comparison.

Some folks get lucky with a nice camera with good glass -- others don't. It's taken the better part of a year to figure out the problems -- with cameras tied up in service for months. Sony even tried to replace the Z7U stock lens with a new lens as a fix -- but the problem persisted. The probem seems to be partly the glass and partially the camera design. After months of problems they offered me a new camera (replacement) and when Sony took the new camera out of the box to check, guess what . . . it had a back focus issue also (but not as bad as the camera which they replaced).

If you want to PM me, I can offer you more info. about the problems with lens issues.

Thanks again. I look forward to seeing how you do with the stock lens and the distance read out test.

Ian

Hi Ian

I just did a test. The tape measure in my office only goes to 16 feet, but with the camera focussed at 16ft with the standard lens I get a reading of 18ft in the display. I'll hold off contacting Sony until I hear how you get on, so please keep us informed - thanks.

Thanks Mike for running this test. It seems that all of the Z7 cameras have problems in this dept. This issue is bad enough -- but the main reason I'm interested in it is that most, if not all, Z7's have back focus issues of some sort -- so small in some cases it's not an issue -- in many it's a major problem.

Your info. is helpful in determining that this "mathematical" discrepancy may be part of a problem that's coming to light about the match of the lens with the camera and its software which determines the way manual focus works with Z7.

I am collecting data from others, and your assistance is appreciated.

Thanks . . .

Ian

Hi Ian,

I did the back focus flange adjustment when first purchasing the camera - although not against a pure blank wall as suggested. I find the auto focus troublesome in low light but have adjusted my style to compensate.

I did your 24' test (from wall to lens frontage) and manual focus is sharp between 26-27 feet. :(

Camera purchased in New Zealand about 12 months ago - Serial 5103xx

Any updates appreciated.

Regards
John