I recently acquired some lens cleaning fluid from a camera chain store (Jessops if anyone's interested). Thinking about it now, is this fluid likely to damage the coating on the front element of my lens? Should I try to find a more expensive cleaning fluid, or does it not particularly matter?
Why do you think that Jessops (a long established company) would sell something named "lens cleaning fluid" which would damage a lens ?
Should I try to find a more expensive cleaning fluid, or does it not particularly matter?
Why would paying more make you feel better ? Paying less usually makes me feel better. Try it, you might get used to it.
I'd be surprised if there's any significant difference between more expensive and less expensive lens cleaning fluid.
The lens coating consists of as a thin coat of various minerals. The idea is to mitigate reflections from the polished glass surface. Uncoated glass reflects away 8% while coated glass reflects away 2%. A multi-element lens array can lose 30% or more as each element reflects thus the total loss is huge. Worst, the internal reflections bathe the film or sensor with stray light that destroys contrast, we are talking flare. The optimum coat thickness is 1/4 the wavelength. This will be specific for just one color. A modern lens is multi-coated to control reflections from the various colors. A modern lens array can have 6 thru 12 coats. The coat is quite durable. At the factory, ethyl alcohol is used to clean the lens as it is assembled. The real danger is aggressive scrubbing can alter the thickness of the coat.
While not actually recommending that you clean this way, I use ordinary Windex on my lenses. Never harmed one in the 60 years I have been working with this stuff.