"close up" filters

[Blind Bruce]

I found what I think are close up filters in an old camera bag. There are three of them made by Hoya. They are labeled +1, +2, and +4. I tried them on my kit 18 - 55 mm lens and can see no difference in focusinc close up.
How are these filters supposed to behave?

 

[Watchful]

Those are sometimes called diopters, and will create a very slight magnification and can be stacked, but will add chromatic aberration and internal reflections.

 

[Dave442]

I had a similar set of those many years ago, I think they were a Christmas gift. They should be allowing you to focus much closer. I remember stacking them together to increase the effect.

However, as noted above, they do degrade the recorded image. It is a cheap way to try out some macro photography to see if you have an interest.

One of the first lenses I bought for my DSLR was a macro lens, I felt it was a deal compared to trying to get a decent image using the close-up filters.

 

[wfooshee]

If they are indeed closeup adapters, they should be allowing you to focus much closer than you can without.
I don't have any that fit my Nikon lenses, but i have the ones in my Dad's Voigtlander Ultramatic kit from the 60s, and I have an adapter to mount those lenses on the Nikon. So.........

The pieces/parts:

Assembled and stacked:

Shot of a laptop CPU heat sink:

You can see the color fringes, which get worse the farther out from center you look. That's the chromatic aberration these things will give.

 

[Blind Bruce]

Will the autofocus (either spot or matrix), of the D7200, work just like it does without these "diopters"?

 

[wfooshee]

It should. The AF sensors act on what they see. In my case, I had an old non-AF lens, but I did have the focus confirm light in the viewfinder.

 

[petrochemist]

They are almost certainly close up diopters (the +number is the strength measured in diopters - which are actually the reciprocal of the focal length in meters - you can combine combinations where the total is the sum of the individual diopters being used)

You should find that with the 'filters' the focusing scale on the lens is further than the distance to the subject.
IIRC With a +1 fitted the lens can't focus more than 1m away, with the +4 fitted 25cm will be your Maximum distance.
More useful than having the lens focused at infinity is having the lens focused near minimum, where the additional lens will allow you to get closer & make the image bigger.
Photographers into macro work generally fine tune focus by moving the camera closer to/further from the subject leaving the focusing ring set at the position that gives the magnification they're after.

The optical quality of these close up devices vary considerably, better quality ones have multiple elements and give considerably less chromatic aberration than the cheap ones.