Temperaturni preizkus SD pomnilnih kartic (popravek prvega preizkusa) - SLO and ENG

 

»Če zaključim o temperaturnem preizkusu. Naše fotografije bodo ostale shranjene, tudi če kartico izpostavimo soncu polarnim temperaturam. Kartico ATP nato lahko takoj damo v čitalec, Kodak (komercialno) pa moramo najprej dati na sobno temperature, šele nato je možno iz nje brati podatke.«

Takole se je v članku »Test občutljivosti pomnilne kartice na temperaturo in sevanje« zaključil zapis in ocena glede temperaturnega preizkusa do +85^o.

Ko sem odprl vrtca sem imel kaj videti. Največji strah je bil, ali so podatki shranjeni in ali jih bom lahko prenesl na računalnik. Razen tega, da kartica včasih izgubi kontakt je na njo še vedno možno pisati in brati podatke.

 

Po treh tednih pa sem šel na nekajdnevno potovanje in za kompaktno kamero poiskal tudi SD kartice nižjih kapacitet. Nikoli ne veš ali boš imel dovolj spomina za fotografiranje. Med drugimi sta šli z menoj tudi že znani kartici iz preizkusa. ATP 4GB SDHC Class6 (deklarirano za industrijsko rabo) katero sem vstavil v DSLR kamero in Kodak 256MB (deklarirano za komercialno rabo), ki je našla mesto v kompaktni kameri.

Po nekaj posnetkih s kompaktno kamero, pa se je začela samodejno ugašati. Ko sem pritisnil prožilec, se je kamera ugasnila. Nekajkrat sem poizkusil ponoviti posnetek a vedno enako. Šele po nekajkratnem preizkusu pa se je na zaslonu pokazal napis »No memory card«. Odprem vratca za katerimi je kartica in takoj sem opazil veliko režo na lepljenem delu tankega dela kartice. Takoj mi je bilo jasno, da kartica, ki ni bila deklarirana za industrijsko uporabo in je izdelana iz plastike, ki ne zdrži tako visokih temperatur kot smo mi preizkušali (nad 70^o). Zanimivo, da ni opazil odprtinetega niti preizkuševalec Željko po laboratorijskem preizkusu, niti jaz sam kakšen teden po preizkusu, ko sem kartice dobil nazaj. Torej se je deformacija zgodila šele kasneje. Prav tako so sedaj dobro opazni deformirani deli nad kontakti kartice in na spodnjem delu kjer je kartica na štirih delih že tovarniško mehansko sestavljena. Temperaturne spremembe so opravile svoje delo in slabši material na ne industrijski kartici dodobra deformirale. Na kartici so sicer še vedno shranjeni podatki. Tudi zapisujem in berem lahko še vedno iz nje. Vendar pa mi vsake toliko časa izgubi kontakt s tem pa je izgubila na sigurnosti delovanja, zato bo romala v arhiv uničenih kartic.

Material kartice, ki je deklariran za samo 70^oC se je pri 85^oC dodobra deformiral. A zanimivo, da ne med ali takoj po preizkusu.

Na delih kjer je bil material ob sestavljanju kartice že deformiran je tudi prišlo do dodatne dobro vidne deformacije materiala.

Plastika komercialne kartice se je nad kovinskimi kontakti pri 85^oC prav tako deformirala.

Obenem pa se je plastika po daljši stranici tudi skrivala. Prav zato je najbrž večkrat izgubljen kontakt.

 

Prav na podlagi tega primera lahko vidimo, kako prav nam pridejo podatki o standardih, da se jih podjetja tudi v veliki meri držijo in da ne smemo preveč pretiravati v njihovem izkoriščanju. Predvsem pa še ena izkušnja več, da je potrebno določeno kakovost ali preizkus opraviti na več načinov ter v daljših časovnih obdobjih in če je mogoče na več enakih testiranih enotah.

 

Za konec pa še popravek zaključka iz prvega zapisa. Večina uporabnikov uporablja komercialne kartice, ki so deklarirane za delovanje do +70^o. V veliki večini primerov te visoke temperature nikoli ne boste dosegli, zato je za normalnega foto uporabnika tudi komercialna kartica povsem zadovoljiva. No v našem testu smo jo preizkusili pri +85^o in material, ki ni namenjen niti deklariran za tako temperaturo je popustil. Torej krivda ni na strani proizvajalca (v tem primeru Kodak) saj smo kartico sami postavili v previsoko temperaturno območje.

Vsekakor pa še vedno velja pravilo, da vaših kamer kot tudi baterij in kartic ne puščajte na direktnem močnem soncu, še manj za steklom avtomobila.

 

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English

I concluded our testing of two different memory cards in extreme conditions with these words:

»Both cards work outside specified operating temperatures, however, the Kodak card just couldn’t cope with the shock therapy, but it kept the data safe in all conditions. Which, after all, is the most important factor. Your pictures will be retained even if the card is left in the summer sun or in the polar night. The ATP card can be read by the reader at any temperature, but the Kodak card needed to be warmed up first.«

 

Little did I know.

After opening the card door, I was a bit shocked. I was very much afraid that the data was lost or that it wouldn't be possible to copy it to the computer. However, it all worked out perfectly well, apart from the card losing contact every now and then.

 

Three weeks later, I went on a short trip, so I took a few small SD cards with me. There's never enough memory, after all. I also took the two cards I already tested. The ATP 4 GB SDHC Class 6 (industrial grade) which I used in my DSLR camera and the Kodak 256 MB (commercial grade) which was placed into the compact camera.

 

After a few shots, though, the camera started shutting down. Press the shutter, watch the camera shut down. Not a very pleasant experience. After a few futile attempts to get things working, a »No memory card« warning showed up. After opening up the memory card door, I immediately noticed a large gap where the two halves of the card were molded together. Obviously, the card couldn't stand the high temperatures we exposed it to, which were well above its specifications. Oddly enough, neither our resident lab tester Željko nor I noticed anything a week after the test was concluded. Obviously, this structural defect must have occured later. Also, above the contacts and at the four points where the both halves are joined, deformations were apparent. The high temperature deformed the non-industrial material. Still, the card retained its data. It's also possible to use it in a camera. However, it tends to lose contact every now and then, making it unsuitable for serious use.

This card was specified for temperatures up to 70 °C. At 85 °C, the materials couldn’t take it anymore. However, the changes didn't become apparent till much later.

In the places where the material was shaped in manufacture, additional deformations occurred.

Also, at the points above the contacts, the plastic lost its shape at 85 °C.

Furthermore, on the longer side, the whole thing got bent. This is probably what lead to contact loss.

 

This goes to show how useful the operating specifications are and why you should never abuse your equipment beyond them. Most of all, it’s another experience confirming that some thing just have to be tested in the long term, and if possible, on more than one sample.

 

To conclude, let me amend the conclusion from the first test. Most photographers use commercial cards, which are specified for up to 70 °C. In most cases, such temperatures will never be achieved, making these cards perfectly good for everyday use. However, our test pushed it beyond the limits, to 85 °C, causing serious defects in the material. So, it’s hardly Kodak’s fault that the card failed. After all, it was used in ways for which it was never intended.

 

Still, don’t leave your cameras, cards and batteries in direct sunlight, let alone on your card dashboard. It just might be pushing them a bit too hard.