The nature of photographic media has changed. That is obvious part; but what can surprise you is that lens filters that worked so well with your film cameras don't always achieve same results in digital realm. Photographers who've discovered this are either abandoning their old filters and using nothing or using whatever software comes standard with their Photoshop or similar program. If you're interested in getting same quality for your portrait photography that you used to get with film and filters, you need to know that it can be done!
Like many people who’ve made switch from film cameras to digital, I’ve discovered that lens tools I once used so effectively on my cameras to soften, diffuse and vignette my images for quality “finished” professional results won’t do for digital what they did for film.
I’m sure it’s arguable by some that their diffusers still work fine, and I too have discovered that some tools still work okay under some circumstances but as I’ve learned, not all circumstances; my Ziess Softar #1 seemed to offer decent results when photographing a single subject in studio but not without substantial cost to image contrast. I also knew that black netting diffuser that I used so effectively with my Lindahl Bell-o-Shade and medium format camera no longer worked on new digital zoom lens without showing lines in image. I also knew that my other softeners made images look too out of focus. Not a risk I was willing to take professionally so I just stopped using Lindahl shade and drop-down filters. Intimidated, I stopped using any filters.
Then it happened. A savvy carriage trade-minded customer brought in a wall portrait that she had purchased several years ago by a photographer obviously using medium format lens tools like I was used to using in past with my film camera. She wanted her new wall portraits to have that same “softened” look. So I arrived at portrait session armed with my digital camera equipped with very mild Softar Filter that worked okay in studio on single subjects.
Understand that I knew any diffusion used on an entire family group portrait would be more exaggerated by their relative head sizes but I had explained that to her and she assured me she liked her portrait images “very soft”.
While images looked good on small camera monitor, once I opened them up in Photoshop and printed them out as proofs I knew they were too soft. I called a colleague who is a digital expert and explained to him what I had done. He told me that you simply cannot use on-lens filters anymore for professional softening and diffusion without creating mush on 35mm type digital camera images. This leaves special effects job now to computer and not camera. I told him I’d tried using Photoshop CS in past for their diffusion tools and what I got didn’t look like real photography, at best it degraded my images or made them look grainy and out of focus. He agreed that Photoshop’s filters weren’t right tools either to mimic professional photography filters of past but told me that there is a company that has a software program that is a plug-in for my Photoshop and has filter tools to recreate believable results for various levels of softening and diffusion.