Minimum focus distance

[Ken Anderson]

Hi, I'm new to the forum and have a question about minimum focus distance (MFD)..

Is it possible to focus on objects that are closer than the MFD?

For example, if my camera lens has a MFD of 4 feet, could I focus on an object that is 1 or 2 feet away, by adjusting the camera's settings?

I realize it depends on what lens and camera are used. But in general terms, how much closer can (or theoretically could) a lens focus than the MFD? Twice as close, or...?

Thanks for helping me out...

 

[Ls3D]

In my experience it means what is clearly states, but I don't run an optics lab or anything.

-Shea

 

[Overread19 7]

nope you can't focus any closer than the minimum focusing distance and there are no settings in the camera which can alter this.
However you can use filters (close up or macro) and also for SLR type cameras use extension tubes to reduce the minimum focusing distance of a lens. Of course there are drawbacks - adding more glass means that there is a reduction in image quality - if your using a topend filter this is minimal to unnoticable on a good lens, but of course cheaper filters will give worse performance.
Also extension tubes will remove infinity focus on a lens - so whilst you can focus closer to things you can't focus on further off things anymore

 

[dxqcanada1]

Stopping down the aperture.

You can achieve a greater depth of field by using a smaller aperture.
It is difficult to say exactly how much you will get ... unless your camera has a stop down switch (so you can actually see it through the viewfinder).

 

[ksmattfish]

You can google "DOF calculator", and find numerous websites that will help you figure the DOF possible for your lens.

In addition to close-up filters and extension tubes some people use an adapter that allows lenses to be mounted backwards. I'm not sure it works with all lenses.

 

[Battou]

No, not with out proper filters and or extention tubes.

Minimum focusing distance is it's minimum how ever with Closeup filters or an extention tube you can exceed it.

I use a set of Tiffen closeup filters or my bellows ...sometimes both when I want to get close.

*EDIT* Dammit, I need to read the whole thread before answering.....

 

[Ken Anderson]

Thanks for your info, everyone. It's most appreciated.

If possible, I'd like to get some clarification...

Overread (and Battou) - you're saying that you can't focus any closer than the MFD, and there are no settings in the camera which can change this.

dxqcanada - you are saying that you can focus closer than the MFD, by stepping down the aperture, and achieving a greater depth of field?

 

[tsaraleksi]

Stopping down would give you a little bit of gain, but probably not a ton. Other than that, you need to look at add on gear that will help, like the tubes and filters that were mentioned in the previous posts. I have never used the extension tubes but everything I've seen indicates that they are a pretty good way to get into macro. In my experience close-up filters can really do terrible things to your image quality but that may just be because I was using old close-up filters.

 

[Battou]

Overread (and Battou) - you're saying that you can't focus any closer than the MFD, and there are no settings in the camera which can change this.

Exactly, you need additional equipment in order to reduce the minimum focusing distance.

If you are using AF and you go within the minimum focusing distance the AF will dsearch and search untill it gives up or finds something within the focusing range. If you are manual focusing the focusing ring just stops at a certain point and thats all she wrote.

 

[Ken Anderson]

So obviously, there is no way a lens with a MFD of 4 feet could focus on objects that are much closer, like 1 or 2 feet away, regardless of the camera's settings (aperture, focal length, etc.).
Not without additional equipment.

Thanks for clarifying this issue for me.