I have two spots that are in the same location on my images. More pronounced at smaller apertures. Sent my lens into Nikon but the spots are still there. Is this a sensor issue or should i send the lens back to Nikon.
What you are seeing is dust or debris on the camera sensor. It's not a lens-related problem. There are various methods of cleaning the sensor (or of having it cleaned for you) - check out previous discussions in this Forum
Sounds like something on the sensor. Have you tried the "clean the sensor" option in the setup menu? If that doesn't work I have had good luck fixing this with a light puff of air from my squeeze bulb. There is a menu option to "Lock mirror up for cleaning" to leave the shutter open, I keep the opening pointed down and lightly blow on the sensor with a squeeze bulb. Then turn the camera off and the shutter will close. Good Luck!
I agree with the others that it's likely dust on the sensor (actually the low pass filter). As Scott mentioned, check out one of your other lenses to see if the spots are still there. If they are, you know the problem is dust or dirt on the sensor.
The D700 has an "automatic image sensor cleaning" ability. For whatever reason, the default setting for the cleaner is off, perhaps to preserve battery power. Do you have it on or off?
I've found the auto cleaner actually works quite well. I'm at about 15,000 actuations into my D700 and I haven't had to manually clean the sensor yet. With my D200, I was manually cleaning the sensor every 5,000-7,500 actuations.
If the problem is dust and dirt first try using the camera's cleaner by selecting "Clean now." (page 393 of your manual). If that doesn't work after 2-3 tries, go through the general steps of the Copperhill cleaning methods, by first blowing the dust out, then continuing on as necessary.
I'd also turn your D700 auto cleaner on as a preventative measure. I use the option "Clean at startup & shutdown." As mentioned, it works well for me. (page 394 of your manual). This setting is in your setup menu.
Thank you for all your input on this problem. It doesn't seem to be on every lens but definitely on more than one. Only appears at the smaller apertures though. (I know this doesn't make sense) I think it's the sensor. The self clean doesn't seem to help. Will pick up one of the kits and cleaner.
Brian is 100% right about the spots showing up at the smaller apertures.
I have a couple of comments on the cleaning of the sensor/low-pass filter that I'd like to pass on, based on my experience cleaning my own sensors.
Use the least "invasive," for lack of a better word, method, one by one, through the Copper Hill method, to clean your sensor. That is the essence of the original, and now modified many times, Copper Hill Method, which is designed to prevent anyone from cleaning their sensor into more trouble than they have already. That's why I suggested using the internal cleaner first, just in case it worked at this point, which I doubted. It sounds like the two spots are pretty well fused on to the exterior of the sensor.
Even though the D700's own cleaning system didn't work to remove the existing spots, I'd still have it on by default, as it can prevent problems. I'd have it set to clean each time you turn your D700 on or off.
I really like the products of Visible Dust to help you carry out the Copper Hill cleaning method steps. I have gone through many devices to successfully clean my sensors over the years, since I got my first DSLR, a D70, and have found that the claims of improvement by Visible Dust are true, at least for me. They do add to the investment cost of cleaning your sensor, but I believe the products are worth the expense.
For example, the first step is to try to blow the dirt or dust off the sensor. (By the way, make sure you use fresh batteries when you clean the sensor. You don't want the mirror coming down prematurely and jamming with something your using to clean the sensor. It could damage the mirror mechanism and/or the sensor.) I have found that the anti-static Zeeion Blower is more effective than any other blower on the market, such as the tried and true Giottos Rocket. My evidence is anecdotal, but I do believe in the product. (I have absolutely no connection with the Visible Dust company.)
The second step of the process, if the first doesn't work out is to brush off the dirt or dust from the sensor. Here again I like Visible Dust's Arctic Butterfly better than using some kind of sensor brush and getting it to attract dust and dirt by blowing air through it. I have found I seem to get a more attractive charge via the Arctic Butterfly.
I would add here that the Visible Dust Quasar Sensor Loupe, LED lighted magnifying glass is invaluable in cleaning sensors. It fits perfectly over the lens opening in your Nikon DSLR, and makes it easy to see the dust and dirt particles on your sensor so you know exactly what you need to remove, and if you've actually removed it.
For the wet method of cleaning, like most others, I move to the products of Photographic Solutions. (I have no connection with this company either.) They are the basis of the wet method listed directly by Copper Hill. Their Eclipse cleaner is very pure methanol. The purity of the product is very important as it tends to not leave a film on the sensor when it dries off. You surely don't want to leave a film residue on your sensor. It can have a negative affect on your photo quality, and it can be an attractant for dust and dirt. Methanol is an excellent cleaner for optics with dust and dirt which is why it's suggested. I use sensor swabs to apply the Eclipse solution on the sensor to wet clean it. I like them better than using PecPads because they are premade and don't have the disadvantage of possibly falling apart, and because Photographic Solutions recommends that PecPads are not used to clean DSLR sensors, that Sensor Swabs are their product of choice. PecPads are recommended for cleaning lenses. For the D700 the size 3 Sensor Swab is the recommended size. (The Sensor Swab Plus product is the same as the Sensor Swab, but they are pre-moistened with Eclipse liquid.)
I think that will about do it. Good luck with your cleaning.