50mm Nikon 1.8D centre bright spot

[negative_optimist]

I recently bought the Nikon 50mm 1.8D for my D90. I quite interested to see how much my shots will be improved over my 35mm DX lens which has been my only prime lens. I took it out down to the White Cliffs of Over and shot a few pics of people catching the sun. When I checked these out later there was a bright spot in the centre of each image. Not really pronounced but noticeable against a blue sky. Am I doing something wrong? I shot all of these with my eye to the viewfinder so not sure if it's light entering from behind.
One last thing about the lens is I expected the actual focal effect to look longer than 50mm due to the smaller sensor on my D90. The lens actually matches how my eye sees the scene which I though was the reason this lens is so popular as a prime. Have I got this wrong?

[Cathus]

can u post an example or 2?

[MattUK]

Is the spot uniform? Precisely centered? If not, it could be a dust spot.

As for the focal length, are you basing this on a feeling, or have you calculated the results?

[OldBoy]

Originally Posted by negative_optimist

One last thing about the lens is I expected the actual focal effect to look longer than 50mm due to the smaller sensor on my D90. The lens actually matches how my eye sees the scene which I though was the reason this lens is so popular as a prime. Have I got this wrong?

The focal length is the same regardless of the size of the sensor, what does change is the field of view, so in you case 50mm on your camera gives the same as a 75mm lens on a full frame camera.

[greenwing]

I think that your spot is a reflection from the sensor to the rear element of the lens and back to the sensor. There's an off chance that it could be a reflection from any UV or other filter that you have fitted, so you could try removing that, but I'd expect that to be off-centre.

There's not much that can be done about it, as far as I know. It just seems to happen with some lens/camera combinations - not all cameras of a type, or all lenses of a type. Just some combinations.

Chris

[negative_optimist]

I've attached some example pictures that I took this weekend. The spot is there, but looks subtle on screen compared to the preview on my camera. It's central on each image (it's sightly up and to the left of one image due to some slight cropping I did). It's annoying since you can see it when your eye wonders around the image. If you look directly at the centre it's harder to see. I guess I can correct with software editing.
I don't have a filter attached to this lens as the front element is quite recessed anyway.





The images have a uniform blue here so maybe this is an exception I can live with if it's an issue with the lens and camera combination.

[ianpinion]

That looks like a dust spot to me, negative optimist, either on your sensor or on the rear element of the lens. Give both a clean and your problem should be cured, but just use the healing brush to remove it from these shots.

[greenwing]

The big spot isn't a dust bunny, though there are a few in there.

It looks exactly as I thought it would. I've seen spots like this discussed several times over at nikonians, and the concensus seems to be reflection from the rear element of the lens. I've taken the liberty of running the image through Topaz Adjust to better show the problem, and then [RANT]realised that I can't just post it into the thread, and do you know I just can't be bothered to post it somewhere else & link to it. Are you listening, Photo Radar team?[/RANT]

Chris

Later: Here's another thread at another place discussing a similar thing.