Black spec on 7100 sensor

Paul pminteriors

Paul pminteriors

Messages
356
Name
Paul
Edit My Images
Yes
Evening all. I have a little problem. I've seen black mark on my 7100 pics lately. I've tried different lens and it still appears. I can also see it thru the viewfinder as well as the pictures. I thought it was a spek on the mirror but on locking mirror up I can see a spec on what I think is the image sensor. Has anyone ever experienced this? No pics on my mobile from camera yet. I've only had it about a month. Still under warranty. Cheers.
 
Im not sure how it would show up in the photos and in the viewfinder with different lens. i've just blown a piece of black dust off the underside of the focus screen, I knew where it was as it was only showing in the viewfinder, one quick puff (with a blower) did it. I wouldn't touch anything inside the camera with the tip of the blower. Post an image like minnnt has asked, I'm sure someone could help.
 
Last edited:
Are you sure the black mark you see in the viewfinder is the same one that appears on your photos? The sensor is not viewable through the viewfinder so the dot you see through the viewfinder is on the lens,mirror or screen.
 
Yes. The mark is defo seen thru the finder and on the pics. As far as I can see there is nothing on the mirror. There is something on the sensor tho. That's what I couldn't understand how I see it thru the finder and see it on the picture. Will post an image today.
 
If you can see it in the viewfinder, it isn't on the sensor. If it's on the sensor, you can't see it in the viewfinder. It's as simple as that. The construction of a DSLR means it has to be that way.

Do this:
minnnt said:
Try taking a picture of a white piece of paper or card at f22ish, iso 100 and post it up.
Click to expand...
 
Yes I know that. It's defo not on the lens so that rules that out. I will post an image today. If I see it thru the finder, and it's not the lens (I've tried 3) where else could it be? For a picture does the mirror move to allow the sensor capture the image...
 
As Stewart says, dark marks on the image are on the sensor, usually only visible on areas of plain tone shot at a high f/number, eg sky. Use a lower f/number like f/4 or f/5.6 and they're usually invisible (depth of focus effect). A rocket blower (£10 Amazon) is usually enough to shift them, but note that the image in inverted on the sensor so a mark top-right of the image will be bottom-right of the sensor as you look at it, though it's unlikely you'll be able to see anything with the naked eye. Stubborn marks may need a wet clean.

Anything visible through the viewfinder will almost certainly be on the underside of the focusing screen, above the mirror (not on or in the lens, or mirror). Rocket blower again, but be careful not to touch anything - the focusing screen surface is very delicate.

Dust is a fact of life. You can chase it away, but it'll be back.
 
Paul pminteriors said:
Will that dust be visible on both the image and viewfinder?
Click to expand...

If you can see marks both on the image and in the viewfinder, they are different bits of dust.
 
I've tried to take a pic with no lens on and can't see anything however. Don't know if this helps tho.
 
Then its coincidence.
Its physically impossible for sensor dust to be seen through the viewfinder. It just can't happen.
Clean the sensor, clean the focus screen, clean the mirror and clean the viewfinder.

Also don't forget what you see on the sensor by looking at it through the mirror box won't be in the same place on the image.


Paul pminteriors said:
Thing is they both appear in roughly the same place.
Click to expand...
 
Don't think you will get much warranty joy with sensor and/or viewfinder dust.

To reiterate anything on the sensor could be reproduced on a photo, but not muck in the viewfinder (good job too with all the little bits in mine)

Just one of the pitfalls with digital cameras although the inbuilt cleaning devices keep it to a minimum, give it a go with the blower and hopefully that will shift it.
 
The mark on the images are from the image sensor and have been cleaned. The other mark that appears in the same place on the viewfinder is in or around the prentaprism somewhere. I kinda knew about not being able to see the mark on the sensor thru the viewfinder but the coincidence had me confused.

What precautions do you take to try and stop dust entering the camera, apart from the obvious.
 
Short of only changing lenses in a clean room (rather impractical!), sensor and VF dust is a fact of life. :( To reduce it, keep the camera facing towards the ground when the lens is off, cap the removed lens as fast as possible after removal and fit the fresh one as fast as possible (while ensuring it's correctly aligned...) Whenever possible, avoid changing lenses in a dusty environment and at this time of year, that includes outdoors - pollen is sticky dust!

Every once in a while, shoot a plain wall at a slow shutter speed and a wide aperture - any sensor dust will show on the resulting shot.
 
Does body armour help or hinder?
Click to expand...

For you or the camera?

Being a bit more sensible, you could take a clean plastic bag to change lenses in when out in breezy/dusty conditions. Dust is unavoidable and reckon you just need to stop worrying too much about it before it spoils your fun.
 
Yup. Dust is fact of life. Usual precautions and be sensible me thinks.

Like the idea about clear plastic bag for the time your on the beach when it's windy and......
 
I usually have one of the large zip-loc type bags in my rucksack, can be used for lens changing and waterproof coat (camera, not me)

Also if its cold outside putting the camera in it to come round at room temperature thus avoiding condensation problems.
 
Last edited:
You must log in or register to reply here.
Back
Top