Should you use a Spotting Scope Magnification Extender?

One of the more common questions we get here at Outdoorsmans is whether or not a customer should add a magnifying extender to their spotting scope kit. 

Magnifying extenders are adapters that you can add to certain spotting scopes to increase their range of magnification. These can be very useful tools. However, in my opinion, they’re only useful in the right conditions.

The Options

There aren’t a lot of options out there, but spotting scope manufacturers such as Swarovski and Leica make these extenders specifically for their scopes. Swarovski makes the M.E 1.7 Magnifying Extender, and Leica makes the Leica Extender 1.8x.

Both of these units will increase the magnification by just under double, which is pretty significant. 

The Leica Extender will work with all Televid APO model spotting scopes. The Swarovski ME, however, will only work with the ATX/STX/BTX line of modular spotting scopes. 

What’s great about these extenders is that they are made to the same specs and held to the same quality standards as the spotting scopes themselves so you will not notice a difference in optical clarity.

However, you will notice a difference in overall brightness when the ME’s are in use. This is natural and not something that you can really avoid. The further light travels to reach its destination (your eye), it gets dimmer. When you use a magnifying extender, you’re increasing that distance the light has to travel. 

This, among other reasons, is why I mentioned that using an M.E, is really only helpful when you have the correct conditions. The other big drawback to M.E’s is that as you increase magnification, you exacerbate heat waves. So you want to make sure that you’re not trying to glass when the heat waves are bad. 

Other than that, M.E’s are pretty useful especially when you’re glassing out to distance with the Swarovski BTX.

The magnification on the ATX/STX/BTX spotting scopes varies with the objective and eyepiece that you use. The angled and straight eyepieces are variable magnification. That range depends which objective you use. 

The 65mm and 85mm have the same magnification range at 25-60x, while the 95mm and 115mm have a range from 30-70x. When you use the BTX eyepiece, the magnification is fixed at 30x with the 65x and 85x and 35x with the 95mm and 115mm.

The 1.7x magnification extender increases the magnification of these systems by almost double. When you’re using the the 65mm and the 85mm the magnification increases to about 42-102x and 51-102x with the 95mm and 115mm objectives. 

This extender will increase the magnification to about 60x for the BTX 95mm and 115mm, and about 51x for the BTX 65mm and 85mm.

Another great use for an extender is if you’re on a sheep or mountain goat hunt where identifying a legal animal is of extreme importance.

The M.E 1.7x quickly and easily attaches via the bayonet catch system, and fits right between the objective and eyepiece.

In the case of the Leica Televid APO, the 1.8x Magnifying Extender fits between the objective and eyepiece modules. It too connects via the bayonet catch on the Televid spotting scope system.

Leica’s extender will increase the magnification by a factor of 1.8x essentially giving you 45-90x zoom on the Televid APO.

These extenders are a very useful piece of equipment to add to your glassing kit, and good to know about when looking to purchase a new spotting scope. They come in handy when you need to identify legal animals as well as when you want to add some versatility to your glassing set up.