Originally posted by Wheatfield Something I've learned over the decades is that there is nothing wrong with subjective opinions, providing the person making the opinion has enough experience to have a valid opinion.
I'd agree, but I'd also add it helps if the person *reading* the opinion has enough experience to put the opinions he is reading into context. For instance, I read that the M50/4 macro lens performs better up close than at infinity. Well, OK, I have enough experience to know that *all* lenses do that. So I interpret the opinion I am reading as meaning that the lens in question demonstrates this effect more than other lenses that the person expressing the opinion has compared it to. Fine. But, while I may know that the performance of the M50/4 at infinity is worse than at 1 foot, and I now know that the difference is "more" than it would be for another lens, I *still* don't know if the 50 macro is actually better or worse at infinity than any *paticular* other lens. Say, the M50/2, which my experience says is perhaps the least sharp 50 Pentax ever made. That is, I know the fall-off in resolution is greater for the M50/4, but it started from so much higher, it might *still* be better at infinity. So I still cannot make a conclusion unless someone offers that specific bit of comparative data as well. But then, I still wouldn't t know if the M50/4 is better at infinity than, say, the kit lens. Or if any of this actually varies with aperture. Or, for that matter, if the differences in resolution are large enough to be noticeable on my particular camera, or if they are enough to trounce other potential IQ advantages of one lens over another (such as bokeh, contrast, or color). All I have is one little piece of data, but ot enough to put it into the context I'd need.
Meaning, I can take you at your word that the M50/4 macro suffers at infinity, but that still doesn't give me enough information to determine if it might nevertheless be an improvement over anything I already at infinity. *You* might know what other lenses it performs better than, and in what ways, and at what apertures, but simply reading a post stating that the M50/4 suffers at infinity, *I* would still have no way of knowing what this might mean in practice.
Anyhow, again, my point isn't to say there is no worthwhile data to collect. Indeed, it could be quite interesting. But we are talking about a pretty big data collection & collating exercise in order to make the information useful.