I’m sure I’m not alone when I say that growing up in the film era has programmed my brain to think of anything at ISO 400 or higher as unusably noisy and something to avoid like the plague. I was brought up using ISO 25 and 64 Kodachrome slide film and then transitioned to ISO 50 Fujifilm Velvia slide stock. I shot so much Velvia in the film era that my mind has been conditioned to think of this as the default normal ISO. Well, two and a half decades after film use fell off a cliff, I still struggle letting go of this notion.
The purpose of this article is to show how wacky this long-held belief of mine is in 2026, maybe as much for myself as for others. I always avoided ISO 200 and 400 film whenever I could, even though at the time I lived in the often dark and dismal UK. So, with that in mind, it’s only really since the advent of mirrorless cameras that I’ve learned to let go of this ridiculous hang-up.
Even with the advent of DSLRs, I never set my Canon cameras above ISO 650 preferring ISO 100 or 200. I’d sometimes venture up to ISO 1250 but always felt guilty about how noisy the images might be. I never liked the noise levels generated on my Canon 6D when I did long exposure landscape astrophotography using my 24mm f/1.4 L lens with the camera set to ISO 3200 or 6400. So much sensor noise and so many hot pixels marked me in a way that reinforced my belief that only low ISO offers a good level of ‘professional’ image quality. When Fuji started making good quality X-series cameras I learnt to be comfortable with ISO 500 and 1250 settings but was always reluctant to push the envelope any higher.
Well, the narrative so far proves that I suffered from ‘ISO anxiety’, but the cure for this did not come with SSRI medication, but rather adapting to shooting birds in flight, a genre that requires manual exposure with a shutter speed determined by the proximity and speed of your quarry and a fully open aperture – both of these being balanced out by a floating ISO (that regularly spikes at ISO 25,600!). When the light gets low at dawn and dusk, or during dull winter days, particularly in dense bushland, there is an obligate need to raise your ISO. Fortunately, today’s full frame mirrorless sensors can yield exceptionally clean files at high ISO, and when they don’t, there is a plethora of software options available to diminish the noise. I won’t discuss the various options here, but the top two standalone programs are probably DxO PureRAW (for Raw files, not JPEGS) and Topaz Denoise AI (for both RAW and JPEG files). The former offers a perpetual licence; the latter is a subscription account. I have a subscription to Adobe Creative Cloud and therefore have Photoshop and Lightroom, so I have access to their excellent AI denoise algorithms. Indeed, both PS and LR use the same underlying AI engine for noise reduction, so no one is better than the other.
A moment ago, I said that shutter speed has to be determined by the nature of the bird you want to photograph. So here is a list of desirable speeds:
1. Small, fast, highly active birds (wrens, finches, honeyeaters, swallows, small passerines etc)
Recommended speed: 1/3200–1/6400 sec (small birds move and flap extremely quickly; freezing them requires the highest shutter speeds)
2. Medium birds (pigeons, doves, terns, gulls, magpies, bee-eaters etc)
Recommended: 1/1600–1/2500 sec (these birds are larger and slower than small passerines, so they can be captured with moderately fast speeds)
3. Birds of prey (hawks, eagles, kites, owls etc)
Recommended: 1/2000–1/2500 sec (large raptors have slower wingbeats than small birds but still require reasonably fast speeds for flight shots)
4. Ducks, geese, and waterfowl
Recommended: 1/1600–1/2500 sec (Ducks have strong, fast wingbeats but are larger-bodied, so they fall between pigeons and raptors in shutter speed needs)
5. Large waders (herons, egrets, storks, ibises, stilts, avocets, oystercatchers etc)
Recommended: 1/1000–1/2000 sec (these birds have slow, deliberate wingbeats and can be frozen at lower speeds than most other flight subjects).
So, the speed needed to freeze motion for BIF can vary greatly from around 1/1000 to 1/8000 sec depending on species, speed and proximity. For very slow-moving birds, 1/500 to 1/1000 can be sufficient, but small birds are the most difficult to capture and are the ones I’ll focus on here as they require the fastest shutter speed which pushes up the floating ISO to ensure a balanced exposure is achieved. The lower the ambient light the higher the ISO and the greater the noise will be.
High ISO doesn’t create noise so much as it reveals the noise that’s already present when the sensor is starved of light. Noise is fundamentally a low‑light problem, not an ISO problem: when photons are scarce, both APS‑C and full‑frame sensors have to amplify a weak signal, and that weak signal contains more randomness. Raising ISO simply boosts whatever the sensor captured— (signal and noise)—so if the exposure is light‑starved, the noise becomes more obvious. Full‑frame sensors handle this better because their larger photosites gather more photons per unit time, giving them a stronger baseline signal before amplification. APS‑C sensors, with smaller photosites, reach the “photon‑starved” point sooner, so noise appears earlier at equivalent ISO values. The key takeaway is that noise comes from insufficient light hitting the sensor, and ISO only determines how much that limited signal is amplified. If the exposure is strong—good light, wide aperture, or slower shutter—both APS‑C and full‑frame can produce remarkably clean high‑ISO files. The problem comes when we are shooting fast small dark birds in the shadowy undergrowth in winter. For this the floating ISO will ramp up and render a much noisier image.
I think it is very important to state that you need to select the appropriate movement freezing shutter speed for the species you want to shoot. It is always far better to have a sharp but noisy image over a soft/blurry but un-noisy image.
I’ve chosen to illustrate this article with images I took of New Holland Honeyeaters flying around my garden. These birds are very busy and never really stop for a breath. They fly erratically, rapidly, unpredictably and are the worst subjects to try and capture with your camera. I already knew that 1/3200 sec isn’t really fast enough for this species, but 1/4000sec is generally okay, especially if your using pre-burst to catch them as they take off. I won’t go into all the autofocus tweaks to facilitate capture, as I want to focus on high ISO as a tool that makes this kind of photography possible. Examine the images here paying attention to the captions, and you can see that ISO 25,600 produces okay images when put through AI denoise in PS, but I’d say you could print this to A4 with no issues, even A3 might be passable. Where the ISO floats down to 18,000, the images are slightly better, but not in any really meaningful way. However, the Nikon Z8 files at ISO 11,400 are very noticeably improved and would print reasonably large. Anything lower will only improve things more. So, forget ISO anxiety and consider developing sharpness anxiety instead!
Remember, high ISO is a necessary attribute to ensure sharp flight images. High ISO today bears no relation to high ISO of yesteryear.
The one bugbear that I have relates to the Pre-Release (pre-capture) mode on the Nikon Z8. It doesn’t allow you to catch images in RAW format, you can only catch them in JPEG format. This means some denoising tools may not be available to you. Still, there are enough high ISO files here for you to see that even JPEGs can be turned into good images up to around ISO 11,400. Of course, there are artifacts that need to be cleaned up after denoising so PS editing time is definitely amplified at high ISO, but for good BIF images, it’s worth it.
So, have fun and ditch the high ISO anxiety 😊 Remember, if you want sharp, dynamic flight images, high ISO isn’t the enemy — hesitation is.