800mm telephoto with 2X doubler

[Abitconfused]

An 800mm lens with a 2X doubler attached. A assume this can be done but is it ever done in real life?

[Black Pearl]

When I worked in a camera store we tried to see how many 2x converters you could attach and still get a shot - it for pretty messy after two

[Dave Humphries]

Hi Ed,

Technically yes I guess, if you don't mind manually focusing (MF) - such a combo is likely to be below f/8 limit of 99% of DSLR camera's AF capability - and assuming the subject makes MF a viable option. Not to mention the support requirements; BIG tripod, probably a gimbal head, etc., because handholding will be out of the question.

In practice, if the intent is to bring far off things closer, 'heat haze' effect is often spoil the shots, this will depend upon local geography, weather and several other factors. Quite apart from this theoretically being so, I experienced these problems even with a bridge camera zoomed to a 1200mm effective focal length (aka angle of view).

So before you spend as much on lens and converters as a family car, it might be worth hiring and trying

If the intent is to bring a small part of a subject that's actually not too far off closer, then you may have more success.
Or perhaps you're thinking of shooting the moon?

What subject(s) did you have in mind and where in the world were you intending to shoot them?

Dave

[Abitconfused]

I don't suppose I would really buy, but I wonder about the limits of existing optics. Truly at some point, as you mentioned, atmosphere, weight, and optics conspire to limit the reach of telephoto lenses. But where is that point? I suppose a 400mm lens with a doubler may be close.

[NorthernFocus]

I don't suppose I would really buy, but I wonder about the limits of existing optics. Truly at some point, as you mentioned, atmosphere, weight, and optics conspire to limit the reach of telephoto lenses. But where is that point? I suppose a 400mm lens with a doubler may be close.

It depends. What is the limiting factor? As a photographer it is presumably IQ. Which is subjective and depends on what one plans to use the photos for. Common, relatively inexpensive hunting/birding scopes have magnification factors well beyond that of an 800mm lens. And many people connect them to P/S cameras and use them as telephoto lenses. Used to ID birds a lot of people are perfectly happy with the results. At the other end of the spectrum many people claim that NASA can read your license plate from hundreds of miles in space. What's possible? What's acceptable? What's affordable? What are you really asking?

[AlwaysOnAuto]

In the early days of Nex-7 ownership, I hooked up a 300mm lens and a 2x converter to it for an effective 900mm or so focal length. I took my tripod and camera out to the driveway and set it up to shoot the street sign hanging at the end of the block up the street. I found it a real challenge to aim it, then to lock down the tripod so it wouldn't sag out of the view finder and then to focus without messing up the setup. I then decided that shooting at those focal lengths was best left to those with more patience than I have and a lot bigger tripod. I should probably try it again, only with my A7ii, but it won't give me the crop factor length advantage.

[Ken MT]

I am quite prepared to use a 100-400 with a 2x converter, on a Canon7d Mk 2, which gives an effective 1280mm. A good tripod, well supported, and suitable weather conditions are prerequisites. Manual focusing is required, and mirror lockup, and remote trigger is helpful. A tripod ring on the lens and a gimbal head allows better balance and less aiming problems.

[rpcrowe]

Is this something like you are asking about?

http://www.pbase.com/liquidstone/16x_tc

However, Romy Ocon's pBase gallery has some wonderful wild bird shots.

http://www.pbase.com/liquidstone

BTW:

I can use a 1.4x TC on my 100-400mm f/4.5-5.6L IS ii lens with my 7D2 camera. This will give me an equivalent 896mm lens and still allow auto focus (albeit a bit downgraded using only the center focus spot). That is about as long as I want or plan to go...

I wonder how the quality with the 1.4x TC would stack up with using the bare lens and cropping to the dimensions of the shot with the 1.4x TC???

Of course, since I own the camera, lens and TC - there is no need for me to keep wondering

[Abitconfused]

Yes, this is perfect!