There could be said to be two names for ISO! Just to confuse the issue!
Way back in my early days of film photography the title was ASA. This was a setting that allowed the film to be exposed at the right level with other camera settings being correct.
Now ISO is the name of the “same” setting! We’re really talking about the speed or sensitivity of the image “recording medium”. ASA measured the speed of film and ISO measures the speed of the digital sensor
With film photography ASA was the indication of how sensitive a film was to light. It was measured in numbers and visible on the film packets (see the image to the right of the film roll). The lower the number the lower the sensitivity of the film and the finer the grain in the shots you’re taking.
In the digital medium, ISO measures the sensitivity of the image sensor. The principles remain and the lower the number the less sensitive your camera is to light and the finer the grain or the less “noise” in the image. The high ISO numbers work in a very similar way to ASA in that the higher ISO numbers will be used in lower light conditions. This then allows faster shutter speed for the required image.
What does ISO actually mean? Well, not much! ASA was the name of the American Standards Association and ISO is the name of the International Standards Organization. Both American organisations and they set the standards! NOT something we need to take too much notice of – just the way they work is what we’re interested in!
So what do we look for?
- Light: Is the subject well lit?
- Grain: Do you want a grainy / noisy shot or one without? Can the noise be avoided?
- Tripod: Will a tripod be needed?
- Moving: Subject – Is the subject moving or stationary?
Bear in mind this point – faster / higher the ISO and the more “noisy” or “grainy” the shot is likely to be. Does it matter to your final picture? How important is it to get the shot in lower or better light?
News and show photographers often have to deal with low light – using high ISO is probably a critical thing to do. When doing that it can bring out some interesting results with light – when I used to photograph bands back in the 70s there often resulted some great lighting examples. Unfortunately I can’t prove it as most of my old negatives are now missing!
Experiment and see what happens – these days no film developing costs make that so much easier. Examples where higher ISO would be preferred or required: concert and art or museum gallery, indoor sport and probably indoor work at weddings and parties… Again – experiment and make sure that where you propose to use your camera is permissable!
If you get a chance to take photographs at an event as a “bit of fun” – do it and make the mistakes when it isn’t important to have top images. If you’re invited to a wedding, take a camera and do informal shots at the reception – sometimes these can be better than the official photos.
Lower ISO settings would be used by any photographer requiring little or no “noise” in their images – clean detailed and very sharp. Good lighting or artificial light assistance will help to keep ISO settings low and the resulting images should be of better quality.
The Auto mode with any camera is fine to use while you get used to a camera if you’ve never used one before. The camera will select an ISO number based on conditions it detects.
I’ll add a comparison image below, showing the difference between a shot at 200 ISO and another at 3200 ISO.
The easiest part to see as this will be the plant stamens – see the difference in the resolution.
Most photographers, once they know how the settings work, will use the manual ISO settings. In the first place when new to photography, keep an eye on the aperture and shutter speed settings while you try adjusting ISO settings. You will see a difference. You will see that an ISO of 800+ will allow faster shutter speeds and smaller aperture settings. Practice and see how you get on.
Make sure, as I have said many times before: Read the Instruction Book to find out how to alter settings and just get out and practice – that costs nothing now but your time.
Related terms: Image Noise / Pixellation / Grain – they are all terms for the image distortion at higher ISO – Grain being the term usually associated with film images
Terms and Acronyms – names and other words associated with Digital Photograph. Free Download of my report here
Inaweza kusemwa kuwa kuna majina mawili kwa ISO! Ni ili tu kuchanganya suala hilo! Katika siku za mwanzo za kazi yangu ya kupiga picha, jina la filamu lilikuwa ASA. Hii ilikuwa kuweka kwamba kuruhusiwa filamu kuwa wazi katika ngazi ya haki na mipangilio mingine ya kamera kuwa sahihi. Sasa ISO ni jina la <unk>same<unk> kuweka! Sisi ni kweli kuzungumza juu ya kasi au unyeti wa picha <unk>rekodi kati<unk>. ASA ni kiwango cha kiwango cha mwangaza wa filamu, na ISO ni kiwango cha kiwango cha mwangaza wa sensorer ya digital, na ASA ni kiwango cha mwangaza wa filamu. Ilikuwa imepimwa kwa idadi na kuonekana kwenye vifurushi vya filamu (tazama picha upande wa kulia wa roll ya filamu). Idadi ya chini ya chini ya unyeti wa filamu na nafaka finer katika shots wewe ni kuchukua. Katika vyombo vya habari digital, ISO hupima unyeti wa sensor picha. Kanuni kubaki na chini ya idadi ya chini kamera yako ni nyeti kwa mwanga na finer nafaka au chini ya "sauti" katika picha. ISO ya juu inafanya kazi kwa njia sawa na ASA, kwa sababu inatumika katika hali ya chini ya mwanga. Hii kisha inaruhusu kasi ya shutter kwa picha inayohitajika. ISO inamaanisha nini? Kwa kweli, si mengi! ASA ni jina la Shirika la Kiwango la Amerika (ASA) na ISO ni jina la Shirika la Kiwango la Kimataifa (ISO). Mashirika yote mawili ya Marekani na wao kuweka viwango! NOT kitu tunahitaji kuchukua taarifa sana ya <unk> tu njia yao ya kazi ni nini sisi <unk> ni nia ya! Kwa hiyo tunatafuta nini? - Nuru: Je, mandhari hiyo ina mwangaza mzuri? -Unataka risasi yenye kelele au moja bila? Je, kelele hiyo yaweza kuepukwa? - Je, kiunzi cha tatu kitahitajiwa? - Kusonga: Subject <unk> Je, somo kusonga au stationary? kumbuka hatua hii <unk> haraka Bear juu ISO na zaidi <unk> noisy <unk> au <unk> grainy <unk> risasi ni uwezekano wa kuwa. Je, ni muhimu kwa picha yako ya mwisho? Ni muhimu sana kupiga picha katika mwanga wa chini au mzuri. Habari na kuonyesha wapiga picha mara nyingi kuwa na kukabiliana na mwanga mdogo <unk> kutumia ISO ya juu ni pengine jambo muhimu kufanya. "Kama unavyoona, hii ni moja ya ""mfano"" wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia wa kuvutia." Kwa bahati mbaya siwezi kuthibitisha hilo kwa kuwa wengi wa negatives yangu ya zamani sasa ni kukosa! Jaribio na kuona nini kinatokea <unk> siku hizi hakuna filamu maendeleo ya gharama kufanya hivyo rahisi sana. Mifano ambapo ISO ya juu ingekuwa preferred au required: tamasha na sanaa au makumbusho gallery, indoor michezo na pengine kazi ya ndani katika harusi na vyama... Tena <unk> majaribio na kuhakikisha kwamba ambapo wewe kupendekeza kutumia kamera yako ni kuruhusiwa! Kama wewe kupata nafasi ya kuchukua picha katika tukio kama <unk>bit ya furaha <unk> kufanya hivyo na kufanya makosa wakati si muhimu kuwa na picha ya juu. Kama wewe ni walioalikwa kwa harusi, kuchukua kamera na kufanya shots informal katika mapokezi <unk> wakati mwingine hizi inaweza kuwa bora kuliko picha rasmi. ISO chini ya kuweka itakuwa kutumika na mpiga picha yoyote inayohitaji kidogo au hakuna <unk> kelele <unk> katika picha zao <unk> safi kina na mkali sana. Mwanga mzuri au msaada wa mwanga wa bandia utasaidia kuweka mipangilio ya ISO chini na picha zinazotokana zinapaswa kuwa na ubora bora. Auto mode na kamera yoyote ni nzuri kutumia wakati wewe kupata kutumika kwa kamera kama wewe kamwe kutumika moja kabla. Kamera itachagua nambari ya ISO kulingana na hali inayogundua. Picha ya chini ya picha ya kulinganisha inaonyesha tofauti kati ya picha ya ISO 200 na picha ya ISO 3200. Sehemu rahisi kuona kama hii itakuwa mmea stamens <unk> kuona tofauti katika azimio. Wapiga picha wengi, mara tu wanapojua jinsi mipangilio inavyofanya kazi, watatumia mipangilio ya ISO ya mwongozo. Kwa mfano, ikiwa unafanya kazi ya picha, angalia pembe na kasi ya shutter wakati wa kurekebisha ISO. Utaona tofauti. ISO 800+ inahakikisha kasi ya shutter ya haraka na pembe ndogo. Jizoeze na uone jinsi unavyoendelea. Hakikisha, kama nimesema mara nyingi kabla: Soma Kitabu cha Maagizo ili kujua jinsi ya kubadilisha mipangilio na tu kupata nje na mazoezi <unk> kwamba gharama kitu sasa lakini muda wako. Image Noise, Pixellation, Grain, na Image Distortion at Higher ISO ni maneno yanayohusiana na picha za filamu, na pia ni jina la picha za digital. Pakua ripoti yangu kwa bure hapa