"It is in my nature to look to the future," says Nick Knight, who started taking photographs in 1979 of East End skinheads, and has been adding to what he refers to as "the conversation of fashion image-making" ever since. He no longer considers what he does as photography and is not altogether happy with the term "image-making" – but he is yet to come up with a better name for it.  Knight has worked through the advent of the internet and a shift towards a fully digital age, which accelerated in the 1990s. Though he continued using his 8x10 Hasselblad until the latter part of the 1990s, he says, "As early as the 1980s I was using post-production things like [Quantel]Paintbox. That allowed you to scan negatives and do things clearly outside the remit of what photography was. I remember it was kept in a glass air-conditioned room that only the operator was allowed inside. It cost £300 an hour to use and it would be like working in some sort of sci-fi situation. I can now do everything that did and more on my iPhone."  Indeed, last year Knight shot a whole campaign for Diesel on his iPhone, which went viral. Since establishing his online fashion broadcasting platform SHOWstudio in 2000, Knight has been keenly aware of the benefits of a vast and engaged digital audience. "We reach millions as opposed to tens of thousands," he says. Detractors of his iPhone work argue that professional images ought to be in the highest resolution. Knight contends he is not interested in how many pixels an image has – what counts is how it is used. He once printed a 9ft-tall picture of a model taken on a webcam. "It was beautiful," he says. It was like a Klimt. I would propose that it is an exciting thing to be doing at this moment. There is a way to print up the images I am making and for them to look amazing."  Today, video work excites Knight as much as traditional image-making. "I made a video with Kanye West last year called Black Skinhead,’ he says. "We 3D-scanned Kanye, motion-captured Kanye, and all of a sudden you can have a real Kanye walking around. These things are fascinating." And what is next? "I want to see my art in space. One has to continue pushing the boundaries."  Miles Aldridge typically shoots on film. "For someone like me who is interested in colour I find that is a far superior starting point," he says. "The reason is very simple; the colour chip in a digital camera is incapable of producing such a wide spectrum of colour." For advertising work Aldridge does shoot digitally. "My use of film informs my use of digital," he says. But is it possible to produce a digital image comparable in quality to one shot on film? "The answer is yes," he says. "The differences are meaningful to me but probably not to the art director or client."  Aldridge’s eye-popping scenes, in which models are transformed into characters from his imagination, have appeared in fashion magazines for more than two decades. Ten years ago he began showing them in galleries and museums. He exhibits large prints, 60-75in wide, which, he says, ‘"viewers can walk right up to and look at the eyelashes in focus.  "Focusing on the eyelashes is the most important lesson I have ever learnt," he adds. "It is something my father [the artist Alan Aldridge] told me and it’s a quite wonderful and simple rule."  Aldridge processes his film conventionally and then scans his negatives. In some cases he will combine two or more negatives, which may be different exposures, to produce the desired effect. He then works with Photoshop to produce his final picture. "The most perfect digital scan you can get is from a Crosfield scanner," he says. "It is a sad thing that these scanners use an operating system that is 10 years old. Many of them were tossed into skips when things went digital. My lab still has one, but it is so old we have to find a scratch-free area every time we use it. It no doubt produces the most superior scan from a negative, and in my opinion all contemporary scanners are substandard."  On set, Aldridge still uses Polaroids, cutting and sticking them together to work out his plan for how to achieve the final image. "I am all for being archaic," he says.  Miles Aldridge’s Carousel: Lithograph and Screenprints, Drawings and Photographs is at the Sims Reed Gallery, London SW1, until October 3  "Some people nerd out on the technology," Josh Olins says, "but cameras and all the software are simply tools to create the perfect image. The most important thing is having a connection with the model and a good concept."  Olins cut his teeth in the traditional way, shooting with analogue cameras, but, he says, "I had to quickly become accustomed to working digitally. Now it is like travelling and working with your developer," he adds. "My digital operator is there on set and we work very closely together. It is a completely different process. It works for different people in different ways, but I think my photography improved by going digital – you see your mistakes as you make them so the learning happens quicker. But, of course, people want an edit at the end of a shoot now."  What sets Olins, 34, apart is his desire to keep things minimal. "A few years ago there was a trend in using filters that would enhance contrast and saturation," he says. "In the end it meant everyone was producing images with a similar quality. What I do is try to keep my work looking as real as possible. I do the minimal amount of retouching."  That is not to say that when the moment is right, Olins shies away from taking advantage of digital manipulation. For the current Balenciaga campaign he used a digital technique to recreate infrared film. "We did a lot of research into infrared film and would have shot it on it but we couldn’t get enough stock. So we worked out a way to recreate how it looks. The challenge was creating the aesthetic without it seeming tacky."
While always cherishing the purity of negative film, fashion photographers are positively embracing the digital image and pushing it to the limit. Georgia Dehn hears from three groundbreaking lensmen