Data Code on Sony TRV950

[Bob J. Trimmer]

I am a new subscriber. I just found this forum this week and am very happy to be a new member. I just purchased a Sony TRV 950. My question is about the readout in data code. No matter how bright the subject, the reading will be shutter 60 AWB F4. It will register Fstops lower (3.4-1.6 )and what ever Gain is necessary, but never any stops above (F8-F22?). I also have a TRV 20 CCD that reads the same way. I also have a Sony Digital 8, It registers all F stops From 1.8-F22.
The exposure always looks good, the color and focus looks good. Has any one noticed readings like this during playback. I would appreciate any feed back. I sent my TRV20 back to Sony while it was under Warranty about two years ago. seems I couldn't make them understand what I was asking. Hope some of you will.

Thanks,
Bobdot

[Frank Granovski]

A lens will have a limit with near open and near closed F stops. Some SLR/Rangfinder and film lenses will even go as low as F32 and as high as F1.2. While other lenses will only go to F16 and F4. F1.8 to F22 is pretty much standard.

[Bryan Beasleigh]

Frank
He's saying his camera maxes out at F4 and while that's the sweet spot for DV it certainly shouldn't be the minimum aperture. I just went through the online manual and nowhere could I find the minimum aperture. The max is 1.6 Wide and 2.8 tele. Perhaps Tommy H will pick up on this.

[Frank Granovski]

Oh, and thanks.

[Yik Kuen]

TRV950's sweet spot is at F4.0. It'll control its shutter speed to maintain the aperture. Although there's an Auto-Shtr setting in the menu, turning it on/off doesn't seem to be working.

[Bob J. Trimmer]

Thanks to Frank Granskovi, Brian Beasleigh and Yik Keun For answering my Question about the readout when Data code is activated on my Sony 950. It has always puzzled me as to why the reading is always F4 even in very bright sunlight.

[Tom Hardwick]

Let's get back to Bob's Basics. What you're saying Bob simply does not compute. You say that 'No matter how bright the subject, the reading will be shutter 60 AWB F4.'

This simply cannot be so, or the exposure of your film would vary hugely depending on whether you were filming a helicoptrer in a bright blue sky to a black cat in a shed. If you've put the camera into the shutter priority mode then yes - the shutter speed will remain at 1/60th sec and the apertures will vary to suit. If you've selected aperture priority then you can select f4 (as you seem to have done) but the auto shutter will vary the speed up and down to compensate for varying light levels.

The 'info' button will reveal what settings (to the nearest half stop only) the camera has chosen to use. Unless there's a fault with your camera's info readout (not unheard of) then your camera is indeed doing this and you're making an error somewhere.

What I suggest you do is this Take the tape out of your 950 and play it back in another camera - preferably another Sony, though a Panny will do (though is never as accurate). What does the 'display' readout say in this new camera?

Come back to us on this as it sounds like we don't all agree what your question really is - as Sony were likewise with your TRV 20.

tom.

[Yik Kuen]

Tom, it's true. 950 tries to maintain at F4.0. I tried that several times.

[Tom Hardwick]

> 950 tries to maintain at F4.0. I tried that several times.

What does this mean " 950 tries to maintain at F4.0" It's just a stupid but fast acting lightmeter. It won't try and maintain anything. If it maintains anything it will be the shutter speed at the default 50 or 60 (NTSC) and then it will vary the aperture between the widest (f1.6 to f2.8) and the smallest (f8). If it did maintain f4 you'd end up with gross over and under-exposure of whole swathes of your footage.

tom.

[Bob J. Trimmer]

Thanks Tom Hardwick for your reply.
I did some testing today, and will show the different readings. I have 3 Sony Camcorders, 1- TRV950 my latest camera, 1-TRV20, 1-TRV 510 Digital 8. These are readings during play back. with data code activated.

TRV 950 & TRV20 TRV 510 D8

Concrete-- Full sun Concrete, Full sun
Auto, 1/60, F4.8, AWB, 0db Auto, 1/60, F 22, AWB. 0db


White Door--- In shade White Door--- In shade
Auto, 1/60, F3.4, AWB, 0db Auto, 1/60, F11. AWB, 0db

Tan Plastic Barrel- Full sun Tan Plastic Barrel-- Full sun
Auto, 1/60, F4, AWB 0db Auto, 1/60, F22, 0db

The 950 & TRV20 Give the same readings. To me the readout on the TRV510 seem more accurate. All tests were just minutes apart.

[Bob J. Trimmer]

I had everything listed in columns, but in sending everything got pushed together. Here are the results again.



TRV 950 & TRV 20------------------------TRV510 Digital 8

Concrete-- Full Sun ------------------------ Concrete-- Full Sun
Auto, 1/60, F4.8, AWB, 0db -----------------Auto, 1/60, F22, AWB, 0db

White Door-- Full Shade ---------------------White Door -- Full Shade
Auto, 1/60, F3.4 AWB, 0db ------------------Auto, 1/60, F11, AWB, 0db

Tan Plastic Barrel- Sun-----------------------Tan Plastic Barrel- Sun
Auto, 1/60, F4, AWB, 0db--------------------Auto, 1/60, F22,AWB, 0db

PLease see previous reply, Hope this one will be ok.

[Yik Kuen]

What I'm trying to say is, the 950 tries to maintain at F4.0 even in very bright condition. It merely plays with the shutter speed to maintain the correct exposure in auto mode.

Even pointing into the bright sky, I can never get any reading smaller than F4.0. In very rare circumstances, I got F5.6 and that's it.

Viewing the datacode for all the footages shot, I never get to see F8.0

[Yik Kuen]

Yup, right - it confuses me further : The shutter speed is always at 60 too!

I got almost the same reading as Bob in those similar environments.

I wonder what's wrong.

[Tom Hardwick]

Well something is wrong chaps, and to me it seems as if the data readouts are what's wrong.
I'd think that concrete in full sun and a white door in full shade are quite unlikely to be just one stop apart. Well - it is possible if the concrete is very dark in colour, but I'm guessing it's a light grey? But I believe that they *are* one stop apart as all three cams tell me they are.

The D8 readings look much more authentic to me. 60 @ f22 looks right for a cam with no ND filter, so have you done as I suggested in my last post and played the 950's tape back in another cam and pushed 'display' again?

Can you do the same test but using extremes of the light meter range? Concrete in sun is fine, but then go indoors and film a carpet in the shade - something you can easily duplicate with all three cams and that will be at least 5 or 6 stops apart. Then post the readings here.

If your readings were to be believed Bob then the D8 would be *far* more effective as a low light cam. Four and a half stops more efficient to be precise, and I doubt very much if this is so.

tom.

[Andre De Clercq]

This is intrigueing, but I know that there have been proposals (and maybe realisations) for traffic control cams, where the adaptivity was done through contiously variable ND filters and another proposal (MIT) was through an adaptive "well drain". One of the advantages with such approaches is that you don't get diffraction with small CCD's. Also strobing is being reduced because of the shtr speed remianing at 1/60