Data Code on Sony TRV950
 

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

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.

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.

Oh, and thanks.

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.

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.

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.

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

> 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.

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.

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.

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

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.

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.

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

But I've looked down into the lens of the TRV950, turned the aperture control wheel and seen those two diaphragm blades go from fully open to fully closed. I simply can't believe that Sony would abandon such a well tried and tested method of controlling the exposure and go for a light dump. But I'm happy to be proved wrong.

tom.

I have Completed futher testing. Here are the results this time.
Tom I played the tape in another camera. It registers the same readings as recorded by the 950. I also did a test on carpet. The readings are.

The 950-- is Auto, 1/60, AWB, F1.6, 18db.
The D8-- Auto, 1/60, AWB, F1.4, 9db.

TRV950--------------------------TRV510--D8
Concrete---------------------------Concrete
Sun------Shade---------------------Sun-------Shade
Auto------Auto---------------------Auto--------Auto
1/60------1/60---------------------1/60--------1/60
F.4-------F.4-----------------------F22---------F6.8
0db-------0db-----------------------0db----------0db
AWB------AWB----------------------AWB---------AWB

My Hand---------------------------My Hand
Sun-------Shade-------------------Sun-----Shade
Auto------Auto----------------------Auto----Auto
1/60-------1/60---------------------1/60----1/60
F5.6-------F4------------------------F22------F4
AWB-------AWB----------------------AWB-----AWB

It appears that the readings that are at F4 --F1.6 are recorded correctly, Any thing above F.4 are not. once in awhile I will see a 5.6(as my hand) . I have never seen an F8 or above. As I stated before, Sony seemed to not be able to understand my question. I even sent them a demo tape. There was no comment.

Again, I hate to bore those who are just passing by, but the readings your D8 cam gives are much more true in the photographic sense. Your D8 shows a three and a half stop difference between concrete in sun and shade - exactly as I would expect it to. The 950 shows no exposure difference, so (unless the exposure on the tape varies wildly - which you don't mention so I guess it doesn't) then

a) either the Info readings are wrong and the lens *is* stopping down

b) an ND8 automatically jumps into place when you go into sunlight.

c) An electronic light dump takes place.

The readings from your hand are even wilder. D8 shows a 5 stop difference and DV shows 1 stop.

Let's back-track. Say you wanted to use the TRV950 at small apertures for large depth of field at telephoto. It looks as if your cam won't 'allow it'. What sort of photographic tool is that?

Here's another test for you to try.

Turn the 950 on and switch to auto exp. Zoom the 950 to telephoto an look down that lens. Have a 'pencil torch' (Maglight) by your ear and shine it on axis down the lens barrel. You should be able to see the diaphragm blades react to the light exactly as they would to sunlight. Do they stop well down as they do in manual?

tom.

Tom, seeing the diafragm moving doesn't exclude the other possibilities..."What kind of photographic tool is that?"...Remember that high end dig photo cams also limit their F settings (mainly for avoiding diffraction) See e.g. http://www.dpreview.com/reviews/nikoncp5400/ . It still looks strange that Sony doesn't mention anything about this behaviour.

I believe there is no iris in the TRV 950, and no ND filters as well. Has anyone looked inside the camera? Is the exposure delt with just electronically "post-CCD"?
I still haven't got ND filters, but I'm sure they will give me better pictures in sunlight. In bright sunlight the picture seems to be a bit "washed out."

I did shine a light into the lens and the iris does respond to the light. The iris is 2 blades,they form a diamond shape which gets smaller as light enters. The results recorded on tape are good. Very close to my other cameras. So I assume it is just something in the recording of the information in the data code section.

Thanks to all of you, who responded to my questions, I was reading on another site about shutter related problems they were experienceing with other models of Sony camcorders. So I guess in this age of high technology, it is difficult for even the designers to solve or know all the little quirks.

Thanks again, I really enjoy having access to this site, It is not like some others, no nonsence, but very informative and to the point.

It seems not so many people are interested in this topic, however I am quite concerned with this issue since the model is supposed to go upto F8, why it does not?


What if you use manual focus? does it ever goes up to F8????

The 950/X10 most certainly does have an iris diaphragm Frode, and it's as Bob describes - a two bladed afair forming a diamond at large apertures and a circle at very small ones. Two blades are always less efficient than 6 bladed ones (as used in the TRV900 and VX2k) but they're cjheaper and generally have less inertia and momentum, so can be made to vary the aperture very quickly indeed.

So the lens does indeed vary from f1.6 to f8 in both the manual and automatic mode, though the readout from tape appears to be incorrect at times. I suspect that the aperture is not shown while shooting simply because the F stop and the T stop vary considerably due to in-built and automatic ND filtration. I'll know more later this month when Sony send me a PDX-10 for testing, and I'll report back here.

tom.

In response to your question about trying to select an F8 in manual mode. I haven't been able to select any F stop. It is my understanding the TRV950 is shutter priority only. It appears to me that, wnen you try to make a change of stops, the only thing that happens is the iris just closes or opens while the selected F stop remains the same. The only thing that happens is the picture is either over or under exposed. I have never seen an exposure F8. Only one time, I was able to get a 5.6 reading was a close up of my hand in full sun. As I stated before the exposure always is good. Also the depth of field seems ok. As I stated before I also have a Sony Digital 8 Camera. It will register every F stop from 1.4 to F22

Hi Bob - I really will be surprised to find that the 950/X10 is shutter priority only. Because of the tiny chips Sony have apparently held the smallest aperture to f8 to limit the destructive diffraction losses and this will mean upping the shutter speed when f8 is reached and the light gets brighter. Is there no menu selection offering "Auto Shutter - on/off"?

The VX2k has f11 as it's smallest selectable stop but the camera will happily shoot at much smaller apertures than this if you don't switch in the ND filters. On replay it'll always say you shot at f11 even if it was using f16, f22 or f32.

Bob, you say: 'wnen you try to make a change of stops, the only thing that happens is the iris just closes or opens while the selected F stop remains the same.'

This doesn't make sense as an opening or closing aperture *is* varying the f stop. The readout may well be wrong (always insisting that you were using f4 or 5.6), but this doesn't alter the fact that the aperture blades are constantly on the move.

But if as you say the exposures are good then all is working well. I just suspect the info readout - that's all.

tom.

Tom, this was discussed in some threads months ago, Auto-Shutter option in most Sony camcorders don't work (might be a bug in the firmware)

I tried, on 950, it doesn't show any difference be it on or off.

Yik, "Auto Shtr" which can be selected "on" or "off" in the menu in many Sony cams works perfect if is being used for the right purpose. First of all it's only meant for "full auto" applications (no prompts !), so not in AE modes or other semi-auto modes where shutter or aperture are being presetted. Of course also full manual is excluded.
It basically allows to make a choice between a locked shutter speed (auto shtr "off"), or a variable one (auto shtr "on") when shooting in "auto"
Selecting the first option the shutter speed is locked at 1/60(1/50) and the aperture closes down at high brightness scenes sometimes far beyond F11, resulting in sharpness reduction due to diffraction effects
The second option will limit the aperture closedown but goes into a higher shutter speed which could result in (background) strobing with high brightness scenes.
So, only in "auto" shooting (nothing prompted !) the shutter speed can be set locked or unlocked in the menu by choosing resp. auto shtr "off" or "on" .