Specifications:

• This brand new mount allows you to attach M39 Lens to your LEICA / L(M) (28-90) camera body
• This item contains lock pin which will allow you to adjust to infinity focus
• There is no ROM connection on the ring so diaphragm control of the lens is set manually
• It is possible to use Macro rings and other accessories
• This is a non-OEM product 
• Material: Metal

Details:

• This mount adapter ring allows you to attach M39 Lens to your LEICA / L(M) (28-90) camera body

• There is no ROM connection on the lens adapter ring so diaphragm control of the lens is set manually

• With this camera mount adapter, it is possible to use Macro rings and other accessories

• High quality material makes the mount adapter ring durable and reliable for long time use

About Lens Filters:

Function:

• Filters are round pieces of glass or plastic that help achieve effects most film cameras can't achieve on their own. Though many of these effects have been integrated into digital single lens reflex (SLR) settings, nothing beats having full control over how your image turns out. Correctly using filters can often make the difference between a good photo and one that really stands out.

Types:

• The following are the kinds of filters most commonly used by photographers.
• Ultraviolet (UV) Filters: Used to protect the lens glass from damage, reduce haze and absorb UV rays.
• Polarizing Filters: Used to reduce glare and haze.
• Neutral Density Filters: Used to allow slow shutter speeds in bright daylight.
• Graduated Neutral Density Filters: Used when one aperture and ISO setting will result in over- or underexposure in part of the photo.
• Warming and Cooling Filters: Warming filters reduce blue tones by bringing out red and orange shades. Cooling filters reduce red and orange tones and bring out blue shades. In digital photography, adjusting the white balance has the same effect.

Effects:

• The use of lens filters can produce a wide range of effects. Determining which effect you're after will dictate your choice of filters.
• UV Filters: Cut through atmospheric haze by reducing the amount of UV rays that get through to the lens.
• Polarizing Filters: Typically used for photographing water or glass. They also increase saturation in color photographs, leading to richer tones.
• Neutral Density Filters: Usually used to show motion when slow shutter speeds would overexpose the image. These filters are particularly useful when photographing rushing water.
• Graduated Neutral Density Filters: These filters are most useful when you are confronted by a situation with two different exposure needs, such as trying to catch detail of both the sky and the ground. Graduated ND filters, which are partly dark and partly clear, allow you to control which portion of the lens receives what amount of light with a single exposure setting.
• Warming Filters: Helpful on dark, overcast days or for photos taken in the shade. They are also must-haves to help counteract the bluish cast of snowy scenes and fluorescent lighting.
• Cooling Filters: Frequently used to negate the yellow glow of photos taken under incandescent light, or from very sunny outdoor shots.

Considerations:

• If you have several different sizes of lenses, buy your filters to fit the largest size lens. Then purchase a step adapter ring from any camera supply store; the ring will allow you to use your filter on multiple lenses so you don't have buy identical filters in various sizes.

How to Use Camera Lens Adapter Rings:

• Purchase a close up lense if you are photographing things like plants, insects, jewelry and maybe even food items. Close up lenses, which screw into the front of the camera lens, contain multiple elements of optical glass and are used to change the focus range of the lens. They come in different magnifications and are sometimes sold in sets. A 1X adapter will halve the focus range of your lens. If your lens could focus at 3 feet, you can now focus at 1.5 feet. With a 2X adapter you could focus .75 feet. They dramatically reduce the depth of field, as is true with all macro photography. They are also usually the least expensive accessory lenses to purchase
• Telephoto Adapter: Buy telephoto adapters if you need to extend the telephoto range of the lens. These also contain multiple optical glass elements and are attached to the rear of the lens and then directly onto the camera. They are more expensive than close lenses and are very camera specific since they need to couple with the camera's autofocus and exposure mechanisms. You need to also be conscious of the weight it will add to the lens. A 2X adapter will turn a 200mm lens into a 400mm lens. It can also be used with zoom telephoto lenses. These adapters are great for sports and wildlife photography and are also used in street photography
• Bellows: Purchase an adapter that will alter the perspective of your camera in the same way a view camera does if you are doing architectural and scenic photography or any assignment where the perspective is critical. You can purchase an adapter like the one pictured at the top of this article from LensBaby (see Resources below). These adapters screw into the front of the lens and allow you to tilt the front element to alter the perspective and eliminate converging lines. Another way is to purchase a bellows like the one pictured here. This option actually provides more control since you have a bellows extension and front element tilt both available. You can always adjust perspective in post production, but you will lose some of the image in the editing process
• Fisheye Adapter: Buy special effects lens adapters like the fisheye adapter (pictured here) if you need to turn your wide-angle lens into a fisheye lens. You can also find polarizing filters to minimize reflections from water and glass. Both of these adapters are useful in general photography and provide a function that cannot be achieved in post production. There are also multiple image adapters, clear spot adapters, soft focus adapters and many more. These are much less useful in the digital age since all of the special effects can be easily created in post production

Package Included:

• 1 x Lens Mount Adapter Ring