Spotty images?

posted December 1st, 2017

These two shots of the moon are taken one after the other. The only things I changed were the f stop and the shutter speed. Can anyone please help and tell me why the second picture has spots on it and the first one doesn't?
Settings for the first shot: f5.6, 1/6400, ISO 400, 140mm
Settings for the second shot: f36, 1/50, ISO 400, 140mm
I've noticed before that sometimes the higher the f stop I use the more spots I have on the resulting image. I only really notice them when the picture has a lot of one solid colour or large patches of colour such as the sky or clouds. If the image is more "busy" they're not so noticeable.
If you know how I can use a higher f stop without getting the spots that would be great too.
Thanks very much.



posted December 1st, 2017
If they are consistently in the same place regardless of the lens you use, then probably dust on your sensor. Otherwise could be spots on the lens...not necessarily the external "large" surface, could be on the internal small surface end..which gets often overlooked but can certainly get dirty while changing lenses. Most likely though, dust on sensor.
posted December 1st, 2017
What @dbj_365 said... bear in mind that at the narrow dof of f/5.6, with the focal point being the moon, things that are closer to you will be out of focus rendering the spots invisible...
posted December 1st, 2017
@dbj_365 @northy Ah, I see. I didn't realise a lower f stop would also affect things inside the camera - I just thought it related to what was in front of the camera. Thanks so much for your replies. So am I now correct in thinking that it's not enough to use the camera's own sensor cleaning which is currently set to clean every time I turn the camera on and off - do I need to get it professionally cleaned?
posted December 1st, 2017
@nickspicsnz ya that in-camera electronic cleaning definitely helps, but inevitably a full clean becomes necessary. Most do take the camera to a shop (or even send in to the manufacturer) to get it "professionally" cleaned, on the other hand if you're a careful and patient type, there's lots of info online about how to clean a sensor. A gentle touch with a proper swab, and a dust puffer..you can do it yourself. But, if worry-free is more your thing then a day or two at a local camera shop that offers sensor cleaning will do it.
posted December 2nd, 2017
I had similar recently which was dust on the sensor. It cost £40 and an overnight stay for the camera with London Camera Exchange. I dare not mess with stuff like that myself!
posted December 2nd, 2017
My husband got cleaning swabs from on line and is now a dab hand at cleaning sensor on my camera. When you change lens point camera down so dust cant drop in. ( thats a 365 tip when i posted last year about spots!!)
posted December 2nd, 2017
Yes, a smaller aperture will show dirt on a sensor. What model camera do you use? Some Nikon models had an issue with oil for the mirror mechanism splattering on the sensor.
posted December 3rd, 2017
@dbj_365 @quietpurplehaze @30pics4jackiesdiamond Thank you for your suggestions. I don't think I'm brave enough to clean the sensor myself and have had a recommendation for a company that does it in Auckland, so will give them a go. However, I may also have to ask my hubby to gen up on how to diy it and he could then be in charge of that - he's always looking for ways to save a bit of money ;) I'll definitely point the lens downwards from now on - thanks for the tip Jackie.
@bill_fe I'm using a Nikon D7200 which I've had for just over a year - I don't know if that's one of the models on the list.
posted December 3rd, 2017
@nickspicsnz The one with issues that I had was a D7000. After getting it cleaned three times under warranty and once more where I paid for it; I learned how to clean it myself. I was terrified at first, but now it's no big deal. I've cleaned my D810 and my D750.
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