So here's a sample of my attempt at a slightly methodical testing of the effects of my hoya filter v.s. no filter. I wanted to see how much image quality I'd lose by using one (the reason I want a filter is to protect the lens). I couldn't find any other comparisons available so this might help anyone else thinking of buying one and wondering... This is a plain old "Hoya HMC" clear filter, costed me about $20 (CAD) new off ebay ($10 for the lens, $10 for shipping). Here's 4 pictures of some lines I drew and a bar code from a receipt lying around. 2 were taken with out a filter, and 2 were taken with the filter. The results of which are which are in the photo comments, but have a look at the picture first and see if you can tell which is which. It's uploaded as a PNG, so right click on the picture, download it, pixel peep it or what ever you want. I'd be interested if anyone knows of a better way to easily and reproducibly test this. Personally, from a few pictures I've taken, I can't tell the difference with or without the lens filter on. Anyone else? comments? To clarify, these are 100% crops, they are 1:1 pixel, not scaled down images. The link to the image in the gallery with the comments on which is which is here : https://www.mu-43.com/gallery/scrap-heap/p1273-test2.html The full size and comments can be seen here : https://www.mu-43.com/gallery/scrap-heap/p1289-test3.html
A small image to judge by, but even then the ones on the left looked crisper, the text especially is getting fuzzy on the right hand images. That was before I checked your link. The EXIF info is a bit of an overkill. :smile: Cheers Ray
The biggest issue with filters is flare. The easiest comparison is to take a picture of a strong light source where the light source is not in the center. Many inferior filters will cause more flare and reflections than the lens by itself. Dj
Adding a flare test First off, I appreciate the time and discipline running a good comparison takes, and applaud you for it! Djarum is right though, and along with your first set of tests, running a second test with an open lamp (or other sharp light source) outside of the image would help judge how effective the coating on the filter is. Flare is often also easier to see than resolution degradation. I pretty much use a filter all the time, at least if I'm not using a tripod, and also try and always use a good lens shade to keep any side glare off the filter.
yes I used a tripod. As for flare... that might be hard for me to check, if I were to take a picture of the sun, it'd move by the time I removed the filter, I should be able to get it close enough I guess. I'm not quite sure a lamp would do it - or maybe my lamps aren't strong enough. Maybe I'll give it a try tomorrow if the suns out. As for being able to notice which pictures were sharper... I'm not sure, even after you said the left were sharper, honestly I don't have the eyes to notice it. Maybe after a few thousand more pictures I'll be able to discern more.
I have just gotten a 40.5mm clear filter for my Oly Kit lens. Its the B+W clear MRC filter. I took some picture tests against a bright halogen bulb, and I couldn't see any difference. I need to do something a little more scientific before I give my conclusion. I will say that this filter does not vignette like a sunpak skylight filter I have for this camera. I believe the B+W is 1mm shallower than some of the other brands of filters.
I was only really worried / testing because I read on another thread people going on about image quality issues etc. I'd used them before on my previous camera but I never gave it a second thought about quality issues. I figured I should check to see that I'm not severely crippling my camera setup or anything - for the same of protecting a relatively cheap lens. It's cloudy and gloomy today so I can't really get any samples but I'll try some out door / intense light photos as soon as I can.
