VIDEO CAMERA 1998

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SUN SHADE

Next August sees the first total solar eclipse visible in England for 72 years and many people are already planning their trips to Cornwall to witness this spectacular event, and record it with their camcorders, myself included.

 

I own a Sony TRV 95 and was a little concerned at pointing it directly at the sun in case any damage was caused to the CCD unit. Various dealers didn't seem to have much idea, but most agreed it wasn't a good idea to aim the camera at such a bright source of light, although they were not sure what the outcome would be.  Sony themselves were most emphatic that the camera should not be pointed at the sun, but cold offer no advice on filters etc. However, people do successfully video eclipses where they have occurred in other parts of the world and I'm sure they don't all bur their cameras out in the process. Can you offer any suggestions?

Brian Beresford,

London E11

 

Pointing a camcorder lens at the sun will damage the CCD image sensor, as surely as you would damage your own eyes by looking directly at it. If you've ever used a magnifying glass on a sunny day to burn things, you will know how powerful sunlight can be. It is possible to safely record a solar eclipse, without the use of filters, and that's to shoot an image of the sun. You could try experimenting with a telescope or a pair of binoculars. The idea is to aim the telescope or bins at the sun, and project an image from the eyepiece onto a screen immediately behind the eyepiece lenses, and this is what you record. You could use filters but I wouldn't recommend it as there's plenty of opportunity for something going wrong and CCDs are very expensive to replace! However, for the record one of the most effective filters for this kind of application is an exposed section of photographic negative.  

 

SUPER SWIZZ?

I was most interested in your reply to David Clough (Video Camera August), regarding the capabilities of the Super VHS format. I have always assumed that the inclusion of 'more than 400-lines' in the specification of certain camcorders was a statement of fact and not faint hope.

 

However, what interests me in the new DV era is that the results of tests on DV camcorders seen to suggest that they do not all achieve 400-lines. In these cases what is the advantage, apart from faultless copies to infinity?

 

One other question if I may. Can one expect that by connecting S-VHS apparatus to each other or to a TV with an S-Video input, using standard SCART cable, S-VHS quality will be transmitted? In my Panasonic NV-HS1000 instruction manual they seem to indicate a different configuration for S-Video, but I have not been able to get a satisfactory answers from local retailers on this issue.

Dr D. H. D. Burbridge

Taunton

 

You will also read on the specification pages of instruction books -- usually in fairly small print, notices that say something like: 'we reserve the right to change the specifications without notice'. That basically means the actual performance of the product need bear no relationship what is printed in the manual. We tend to treat manufacturer's specs as a useful guide, but by no means gospel. It's also worth pointing out that resolution in the real world is dependent on an number of other external factors, including the type of tape used, the connecting cables, the equipment on which the image is analysed, and not forgetting the actual test conditions. It might also interest you to know that a good number of domestic televisions -- including models fitted with S-Video inputs -- are incapable of displaying the fine detail contained in high-band video recordings, which makes the performance of the camcorder largely academic. One last point and this has some bearing on your comments about DV camcorders. Our eyes are far more sensitive to picture noise, than resolution. We tend to notice the noise content in a video image long before the amount of fine detail, and you can get the situation where a noisy high definition image will actually look worse than clean recording made on lower definition equipment. Digital recordings tend to have very low levels of picture noise, and unlike analogue recordings, it doesn't increase when recordings are copied, which is critically important when editing.   

 

THANKS FOR THE MEMORY

I am aware of the fact that NiCad batteries can suffer from memory effects and I am careful to discharge them before recharging. What is the cause of these memory effect and could they occur if the electricity supply is interrupted during recharging?

David Hunt

London NW1

 

We used to get a lot of letters about batteries. Improvements in camcorder power management systems and a new generation of nickel metal hydride or Lithium ion packs have made a life a lot easier for us all. Nevertheless there's still plenty of nicad powered machines out there, so a quick recap wouldn't come amiss. The so-called 'nicad memory' effect usually refers to the way a battery pack gradually looses its ability to hold a full charge. In extreme cases it's possible for a battery pack to loose up to 50% of its capacity in just a few months. Inside a nicad battery there's a bank of individual cells, connected together in series, (and parallel in the case of higher capacity packs), to produce the required voltage. No two cells are exactly alike, and over time the state of charge of the cells in the pack will vary. Fast battery chargers, of the type supplied with camcorders, determine when the battery pack is fully charged by analysing the voltage of the pack, when it senses a small change it decides the pack is charged and cuts off, or reverts to trickle charge. This small change in voltage can occur when just one or two of the cells inside reach full charge, leaving the others and thus the pack as a whole only partially charged. Discharging the pack brings all of the cells back into line once again. NiCad memory develops quickly when packs are repeatedly subjected to shallow charge/discharge cycles or 'top-ups'  -- i.e. the battery is charged before it has been fully discharged. A power failure whilst charge won't damage the battery, it will simply resume charging when the power is restored.

 

GEN LOST

I desperately need help in locating a stand-alone Genlock, which I realise is 'old technology'. I do no have a PC so a frame grabber cannot be used. I simply want to superimpose titles over moving video. I have tried many suppliers but to no avail so far. Hopefully you have access to companies who may still have old stock?

R.C.Dell

Surrey

 

Are you sure you mean a genlock? They are normally used to mix graphics generated on PC (and other devices) with moving video.  A genlock usually requires one of the two video sources to have an external synchronisation facility, enabling the two signals to be combined.  A frame grabber works the other way around, capturing video information and converting it into a PC image file. It sounds as though you want to create a title, shoot it with a camera and combine it with moving video, in which case you need a digital video mixer. In this case one video channel is converted into digital data and stored temporarily in a memory, then read out so that it is in perfect synchronisation with the second channel. That's quite a trick and it doesn't come cheap. Check out the RoMaster DVR-300 and Camlink Vision 1000, both of which are selling in the 400 to 450 price bracket. If you only want to create simple titles, then there are several dedicated title generators on the market, with built-in genlocking facilities. Prices start at around 120.

 

CANADIAN SPECIFIC

I wish to make a video copy, on VHS-C, of some cine film that I shot in Canada several years ago. I would like to send a direct camcorder copy to my relatives in Canada, but I am unsure if they would be able to view the copy on their VCR. Could you tell me if it is feasible, even if it is a case of 'vision-only' and no sound?  I'd appreciate your comments.    

L.B.Allen

Newhaven

 

Bad news I'm afraid. We in the UK use the PAL 625-line/50Hz colour TV system. Over in Canada they use the 525-line/60Hz NTSC system. The two are incompatible and any recording you sent them, made on a PAL camcorder, would be an unviewable mess. Ironically, you would be able to watch recordings sent from Canada quite easily as many recent VCRs can replay NTSC recordings on PAL TVs. Unfortunately this trick doesn't work the other way around. The simplest solution is to have the movie film professional copied onto an NTSC recording, you will find several companies advertising such a service in our classified section. Other alternatives would be to use an NTSC camcorder (maybe next time your relatives are over here, ask them if you can borrow theirs), or you could use a multi-standard 'transcoding' VCR like the Samsung SV-4000W, which can digitally convert video recordings from one standard to another. This machine currently sells for just under 1000.

 

DISTANT VIEW

I am a complete novice where video cameras are concerned and admit to being totally confused with regard to the wealth of models and types on the market. If I detail my requirements perhaps you could suggest some models which generally meet my criteria. Initially I would be seeking a camera, which can be fitted with a prescription lens to the viewfinder, and I would prefer a colour viewer. Then I would require a camera lens equal to the performance of a quality 35mm still camera and a zoom facility, capable of picking up low flying aircraft, without any visible 'judder' in the picture. I would like a camera with extremely simple controls, such as on/off/shoot, without having to fiddle with exposure etc. Then I would prefer to be able to use off- the-shelf batteries. Actual running times should be in the region of 2 hours, plus. I would like to use standard VHS cassettes, or the type, which can be loaded into a conventional video player. Price is of no object and I would prefer total reliability under all operating conditions. Accessories should include a rain shroud.

Keith R. Bennett,

Leighton Buzzard

 

Taking those points one at a time, virtually all camcorders have a 'dioptre' adjustment on the viewfinder eyepiece that can accommodate all but the most extreme vision defects. The zoom lenses fitted to most camcorders can cope easily with recording at air shows etc.; if by 'judder' you mean erratic or jerky zoom action you have no need to worry, the motorised zooms on all current machines are very smooth. All camcorders -- even the most expensive semi-pro machines --have fully automatic focus and exposure systems, designed for effortless point-and-shoot operation. Some camcorders have optional (or supplied) dry battery packs but they are really for emergencies only, the supplied battery packs can be re-charged, and higher capacity models are freely available. You would be very lucky to find any machine that will run for up to 2 hours on a standard battery.

You express a preference for VHS-C, (I hesitate to suggest any VHS/S-VHS machines as they fall down badly on the  price/performance/portability equation) and a colour viewfinder, which narrows the choice to the Panasonic NV-SX50 (800), as the only machine that comes anywhere close to meeting your key requirements. However, I urge you to reconsider some of those criteria, especially concerning the format. It's really not that important as you will almost certainly want to edit or copy your recordings to VHS, in which case the camcorder tape format is irrelevant. That will allow you to broaden your choice of machines to include Hi8 and DVC models. Look through the Buyer's Guide in the back of the magazine, and try out a few for size at your local video dealer.

 

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R. Maybury 1998 2408

 

 

 

 

 

 


 

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