Use of teleconverter?? pros and cons
Question on use of teleconverter...What are the pros and cons?If I wanted a 400mm lens, why wouldn't I get a 200mm and a teleconverter?Thanks,Crutch..

Comments (6)

... there is no free lunch..

Millennium3 wrote:.

Question on use of teleconverter...What are the pros and cons?If I wanted a 400mm lens, why wouldn't I get a 200mm and ateleconverter?.

A 200mm f4 lens + 2x TC = 400mm f8 lens. On some bodies you'll lose autofocus..

There are also other problems, image quality-wise..

Of course, in some situation, a TC is a very good thing, allowing you to "lenghten" your lens with very little weight penalty...

Comment #1

Millennium3 wrote:.

Question on use of teleconverter...What are the pros and cons?If I wanted a 400mm lens, why wouldn't I get a 200mm and ateleconverter?.

It seems a logical solution to me, considering the cost of mid- and big telephotos. Besides, that's the only option for the DSLR-likes which do not have removeable lenses, but DO allow add-ons. Go to and see their samples of the 2.2X 2020 lens shooting Seattle from 2 miles away on a Canon S5. Such teleconverters plus lens cost roughly $150.....much cheaper and seemingly very little sacrifice in image quality. The DSLR-like user chose that camera in the beginning because of the much higher cost of the better camera, therefore image quality is not his highest priority.ngk20000..

Comment #2

Some lenses work well with TCs, and this can be a workable solution to increase focal length. I periodically use a 1.4 TC on my 70-200 f/2.8 with little or no loss of image quality. However, I avoid the 2.0 TC as the IQ really suffers on my lens as I judge the IQ. I may get a few reasonable shots, but the reject rate is very high to the point it is a waste of time for me..

As devnull mentioned, there is a loss of f-stops with TCs that can effect auto focus. A 1.4 TC costs 1 f-stop while a 2.0 TC results in a loss of 2 f-stops..

The effect TCs have on IQ is lens dependent. The super telephoto lenses seem to lend themselves well to TCs. There are a number of photogs that post examples on DPR of single and stacked TCs on these lenses..

Best regards,Doug

Http://thescambaiter.comFighting scammers WW for fun & justice..

Comment #3

Pros? Saves money..

Cons? There are a variety of performance impacts. With the teleconverters, you lose light. As pointed out, from a stop on up depending on the tc. If you use on an already slower range lens, then the added loss of light can require very long exposures. If you used a lens which required some stopping down to get best performance, then the added slowdown could force you into use of a tripod, lose auto focus, or require shutter speeds that don't stop motion, etc..

Most TCs degrade image quality, from a little to a lot. The degradation tends to increase with the "ower" of the tc. 1.4s seem to do OK, 1.7s, usually good enough, and 2x and 3x tcs tend to be really questionable in many uses..

Physical or electronic compatiblity. Some have fit problems, elements of the tc or the lens will not have clearance or could bump with focus changes, etc. Some don't properly transmit the electrical signals between the lens and the body and back..

There are a range of tcs from some makers, some can be used pretty boradly, some fit only certain types of lenses, some of the cheaper ones may actually work better than a good one or dedicated one used on the "wrong" lens..

Not completely perversely but not real handily, the best tcs seem to perform best on the best lenses. Which tend to be used by the people maybe not looking quite so hard for the budget benefits..

Also fit into the mix are auxiliary lenses, also called teleconverters at times. These fit on the filter ring. Some do pretty well, again, there are usually some optical penalties, not all lenses take them well, good ones cost more, vignetting at less than full focal lengths, increasing magnification seems to decrease performance results, etc...

Comment #4

Crutch, you didn't quite give us enough information. Several of the replies sorta skirted the missing information, but giving you 2 answers. Let me be blunt and ask the question: "What kind of camera do you have?" Specifically, we need to know if the lens is removable..

There are two kinds of teleconverters: 1) the kind that mounts between the lens and camera body and 2) the kind that mounts on front of the lens..

I guess your camera has removable lenses. If so, then you can use either kind of teleconverter. If my guess is wrong (and your lens is not removable) you have to use the 2nd kind..

Both can be good or bad. You sorta get what you pay for. They have different characteristics..

The 1st kind (that mounts between the back of the lens and the body always reduce the light gathering ability of the combo. The most common varieties are the 1.4X and the 2X, which reduce the lens speed by 1 and 2 stops, respectively. These converters are quite small. They also allow zoom lenses to operate over their complete range..

In contrast, the 2nd kind (that mounts to the front of the lens) do not affect the lens speed. But that requires this conversion lens to be HUGE! And they only work at the max FL of the host lens. These lenses have different ratios. For example, my front-mounted TC lens for my R1 is a 1.7X variety. They are more expensive than the 1st kind (because there is a lot more glass in them). Some lenses will have difficulty supporting a BIG front-mounted conversion lens..

Charlie DavisNikon 5700 & Sony R1HomePage: http://www.1derful.infoBridge Blog:

Comment #5

Well I think your question is more or less answered, but ....

1) weight.

A long lens can be quite heavy and a converter is light. You know the math already.You can use it on any lenses you have with you so it does add flexibility..

Basically you pack the lens or lenses that represent your usual or expected shooting and keep the TC handy to give yourself an emergency bit of range..

2) better than digital zoom or enlargement.

I've tried this myself and even with a relatively cheap x2 converter it's a nicer result than the enlarged image ( at least away from the borders at good settings )..

3) Loss of light.

Add a x1.4 and you lose 1.4 stops, add a 2x and you lose 2. That means if your 70-300 is f4-5.6 it becomes like a 140-600 f 6-8.3. Bare in mind that a typical 500mm mirror lens is f8 anyway..

4) Optical degredation.

Usually adds (at least) corner softness. Often impacts contrast negatively..

5) Best used with quality primes or zooms at best settings..

Because of the side effects the better your starting lens the better your end result..

If you start with a lens prone to CAs and corner softness this will be amplified. Important to shoot at settings that are your len's best performance..

6) Manual focusing and even exposure.

It's best to expect to do this, rather than anything else. Typically you need a lens set at f4 or lower to use AF, but that's often not a good quality setting for a lens - see (5)..


Pentax K100DFuji S5200Fuji E900PCLinuxOS..

Comment #6

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This question was taken from a support group/message board and re-posted here so others can learn from it.


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