|Bad Bokeh Balls: Canon T2i, Olympus OM H.Zuiko 24mm f/2.8|
You will read, time and time again, that dust and other stuff in the lens doesn't really make much of a difference in the photos it takes. That tends to be true, for the most part, except when it comes to the bokeh. That's where the imperfections start to show up. They are more pronounced when the offender is present on or between the elements closer to the sensor plane(or film plane if you're old school, or a hipster). That's why a little dirt and grime on the outside of the front element doesn't really effect anything, but on the back element, it can cause trouble.
As if getting one bad copy isn't enough, here's the bokeh from the second 24/2.8 that I bought. Described as being perfect in the auction description, it's most glaring flaw was a broken aperture mechanism, but we'll look at that in a later post. This second copy had a speck of black dust that showed up in the bokeh. Is that venus' transit of the sun? You can see the spot about halfway out from the center towards the bottom in both balls.
|Orange eyeballs are watching you.|
In the case of the first lens, it appears that there might be some oil on one of the elements. being the thrifty fellow that I am. I decided I would go inside and see what I could do. The nice thing about manual lenses, is that they are made very sturdily, and there are no electronics inside for you to mess up. Still proceed with caution. Make sure you remember how to get it back to together, and be sure to mark elements so that you know which way they face when you put them back in. A backwards element would render a lens useless. A nice pair of magnetic tweezers and magnetic screwdrivers are really nice as well. the screws inside the lens are tiny, and you don't want to lose them.
Ok. First, for Olympus lenses, if you ever want to find the exploded parts diagram, which, believe it or not, can be quite helpful, check out http://olympus.dementix.org/Hardware/olympus_hw.html. There is a parts diagram for every Olympus OM lens ever made(I think).
If you're going to go in through the backside (minds out of gutters please), you would start by laying it face down on a microfiber cloth, so that nothing on the front element gets scratched.
Now, Is everyone ready for the anti-climax? Dead end. I need to get into the rear elements, which means I needed to get the rear retaining ring off. Unfortunately I couldn't, and I gave up because, as I already have a better copy of this lens that I plan on keeping, this one is going on the auction block. It takes good pictures and just has a minor bokeh problem. There's more value, though, in a lens with an oily squiggle thing in the bokeh balls than a broken lens.
The irony of it all is that the rear element retaining ring screws right off on my second copy of this lens. It's only finger tight.
So you hate me now for letting you down. Hopefully I can remedy that in the future. I will show you the horror that is the flashlight test, I will show you how I got the dust spot out of the bokeh balls on my second copy of the 24mm and what i did to fix the aperture, and I will show you how I cleaned at least some of the fungus out of a 28mm f/2. You'll see me go in through the front side and the through back side. It'll be a good old fashioned party.
This is my dog after all was said and done. She's pooped.
|Stella has been bored to sleep by this post: Canon T2i, EF-s 60mm F/2.8 Macro USM|