Study: Damaged Lens Artifacts

Happy holidays, everybody! I wasn’t able to update the blog last weekend since I was busy and I had to work last Saturday. This coming Christmas is no different for me because I am going to have to work as well. This is Japan and Christmas is nothing more than a Western idea celebrating capitalist ideals. Speaking about Christmas, I have an assignment for you guys this season if you have ever bought an old lens or have inherited one. Read along!

Damaged Lens Artifacts:

Today, I will show you how to check wether a damaged lens element will affect an image or not by using light sources like Christmas lights! Some people claim that damage on a lens’ optic will not show up in the final image, while it is true for minor problems like a patch of fungus it is not true for something more serious like a scratch or chip. Sellers and people on the internet make this claim and I will show you how to test their statement by doing these simple tests.

Dirty Bokeh:

Some damages that are too feint to see with the naked eye without using the help of a light source such as a torch can fool you into thinking that nothing is wrong with a lens but this simple bokeh test can help you determine wether the lens is still OK or not. This test only works in darkness so I do this at night or inside a dark room.

First, focus your lens to it’s minimum focusing distance and stand 1.5-2m away from some Christmas lights or any bright sources of light. This also works on light sources that are far away like some street lamps 60m meters away from you. So long as you can produce clean and clear bokeh balls you are on the right track.

Second, set your lens to it’s maximum aperture and set your exposure settings so that you will get a nice picture with bokeh balls, ISO400 at 1/250s usually works for me. The key to this is to underexpose the bokeh balls a bit so that things will show up.

Examine your picture and zoom into your bokeh balls and look for artifacts. The following images show a few examples of bad bokeh from some of the lenses that I encountered.

HAW_5000.jpgDirt or a bad scratch can cause this artifact to appear. Depending on the cause, it can easily be fixed by cleaning the lens elements in case of dirt or having a professional re-polish the problem element for you and re-coat it after. This particular lens looks immaculately clean but as you can see from the picture above, the lens produces bad bokeh. I am yet to open it again to find the cause but I suspect that a minor scratch in the coating is the cause. More

Repair: Nikkor 50mm f/2K (New-Nikkor)

Hello, readers! Sorry for skipping the past couple of weeks as I was busy with work. It was a very unremarkable month and all I did was work work and work. Couple that with a cold front and you get a very lazy and tired father. Apart from people messaging me that they saw my name in the latest Final Fantasy credits, this month passed on unremarkably and I would like to continue on that tangent by talking about an unremarkable lens today…


Today, we will be talking about the Nikkor 50mm f/2K (New-Nikkor) lens! I was busy in the past few weeks and I cannot decide on which lens I should make a teardown of so I made a poll and this one got the 2nd highest vote. It was such a boring month anyway and it’s just fitting that I make a teardown of a boring lens.

img_1443The Nikkor 50mm f/2K feels heavy and VERY well-built. This feels pleasant in the hands so I would sometimes use this lens just for the heck of it. It has the right heft and balances so well on all cameras without a built-in motor drive/grip. More

Repair: Nikon DE-1 Eye Level Finder

Hello, everybody! I am down with a cold and I had to work yesterday (Saturday) so I do not have much time to update this blog but this morning, I found that somebody donated to the upkeep of this blog and that gave me the will to write this down. Whoever you are, thank you very much for the encouragement! It will be a short one this time. The usual lens tear-downs require around 2-3 nights to write but this should be easier.


We are going to look into a common (and expensive) item for the Nikon F2 camera today – the Nikon DE-1 Eye level finder!

img_1963This is just a standard finder for the Nikon F2 camera. It is really the cheapest option that you could buy back in the days because it is unmetered but since people wanted the ones with the built-in meters for obvious reasons so this one was made is smaller quantities. As time goes by, these finders age and degrade and the prism don’t hold up very well so good ones end up being expensive. The ones that have bad prisms still fetch a nice sum, I think that the cause of this artificial price is collectors. I do not remember these being sold at the current prices 4-5 years ago. More