Nikon 50mm f/1.8D lens: There’s a purple spot in the middle of my photo!

Ahh… the Nikon 50mm f/1.8D lens. An optical masterpiece that no Nikon DSLR owner should be without; especially since it is Nikon’s cheapest lens that is still manufactured today. Every online Nikon lens review loves this lens and can find no fault in it. Well, I found one. A big one! Big enough that it has ruined a few photos and I am considering selling this lens.

When I was searching for the perfect travel camera I wanted pro DSLR quality and performance in a small package and at an affordable price. It seemed impossible at the time, until I coupled the Nikon 50mm f/1.8D lens with the body of the new Nikon D7000. Perfection! Modern DSLR lenses are big and heavy and a pain in the neck (literally) to carry around attached to your already big and heavy DSLR camera body. Even the newer prime lenses are big. But Nikon’s older, yet still manufactured, D lenses lack the built-in focus motors which reduce the weight and size. But, you can still autofocus using the motor from Nikon’s higher end camera bodies, including the D7000. The focus may not be as fast as having a built-in lens motor, but fast enough for most situations. It was this combination that convinced me that a Nikon D7000 with a small prime lens would be my perfect travel camera.

I found the 50mm lens to take incredibly sharp photos and was ideal for low light situations where I could take advantage of the wide aperture. The only fault I could find was that it was somewhat of a telephoto lens. Back in the dark ages, the days of 35mm film, a 50mm lens was a “normal” lens. It saw the world the same as a person would see it. Not wide and not zoomed in. But the D7000 has a DX format sensor, which means it has a 1.5x crop, making the 50mm lens equivalent to a 75mm lens for 35mm film or full frame (FX) sensors. I would see a great shot, put the camera to my eye, and then would start walking backwards in order to fit everything into the frame. This has often had me backing out into traffic or running into parked cars or other objects. I really need to be a bit more careful! The other thing I love and hate about this lens in the bokeh, the not in-focus part of a photo. At f/1.8 the depth of field (DOF) is very shallow, which can be great for portraits of a single person or object where you want a nice creamy blurred out background. But with a group of people, the depth of field increases, which has caused me to miss a few shots because I misjudged the result of my settings. I now carry around depth of field charts in my camera bag. Remember those?

Now for what most of you have wanted to hear; what the REAL issue is with the Nikon 50mm 1.8D lens. A few weeks ago we were at the Oregon coast where I shot a few longer exposures mounted to a tripod using the 50mm lens, somthing I had not previously done before with this lens. Since I do not have any neutral density filters, yet, I stopped the lens down for the longer exposure time. The photos looked good on the screen, but when I got home I was shocked at what I saw on the computer screen. There was a big purple, blue, violet (or whatever color it may be) spot right in the center of EVERY photo that I shot at f/11 to f/22. I checked the lens and the sensor convinced that I had some foreign object or smudge that was ruining my photos, but found nothing. I tried another lens and had no problems. Turning to Google I found that I am not the only one that has had this problem. The theory goes that the light bounces off the sensor in certain conditions causing the purple spot and many people have had this happen from f/11 – f/22. What good is a lens if you can’t stop it down below f/8?

I contacted Nikon about this issue and sent them some sample images. They told me to send them the lens, so I did. A couple of weeks later I got a reply from Nikon saying that the lens needs a cleaning and they want to charge me $45 to do this and ship it back to me. I argue this case and send them about 10 links to other people having this same issue with this lens. I know for a fact that my lens was spotless. They escalate the problem and then send a response saying there is nothing wrong with the lens, and it might be my camera sensor. Yeah right! I have yet to receive my lens back, but once I do, I plan to try it on a couple of other Nikon cameras to see if I can reproduce the purple spot. If I do reproduce it on a different camera, it will be interesting to see what Nikon has to say about that.

Here are the photos with the dreaded purple spot. The only processing these photos have had was converting them from RAW to JPG format and re-sizing:

No purple spot: 1/250 sec at f/8, ISO 180

Purple spot appears: 1/60 second at f/11, ISO 100

Purple spot is more pronounced: 1/30 second at f/16, ISO 100

Oh yeah, we got a purple spot: 1/20 second at f/20, ISO 100

Purple spot: 1/15 second at f/22, ISO 100

Purple spot: 1.3 seconds at f/22, ISO 100

Purple spot: 0.6 seconds at f/22, ISO 100 (a swinging suspension bridge is not a good place to shoot from)

Crop from previous photo: 0.6 seconds at f/22, ISO 100

UPDATE December 15, 2011: I got my lens back from Nikon and just tried it again on my Nikon D7000 and then tried it on a Nikon D90. Shooting it indoors under florescent lighting showed no spot, but going outside to the overcast sky yielded a purple/blue spot on both cameras. Sorry Nikon, but it’s not the sensor, its the lens. This is a great lens for shooting wide open, but it sucks for f/11 and higher where you risk a large spot in the middle of your photo. If you need a pro quality lens for cheap up to f/8, this is your lens. If you need something that can stop down below f/8, I would not buy the Nikon 50mm f/1.8D lens.