Teleconvert on prime lens

[hamlet]

I just saw a Teleconverter on sale and i got an idea to use it on 35mm or 50mm 1.8g to increase your reach. What do you think about this idea? Could this potentially save people lots of money? Is this a good idea?

 

[bratkinson]

Disclaimer: The last teleconverter I owned was bought and used while I was shooting film in the 70s & 80s. I do not currently own a teleconverter.

It's common knowledge that anytime more glass is added either in front of or behind your lens, there will be some image quality degradation. It's a law of physics that every 'transition' layer that light passes through (air-glass/glass-air, etc) some light rays will be altered and not all of them can be 'corrected' by subsquent lenses/layers. So, if you are a big-time pixel peeper, you will definitely see an IQ difference of with and without a teleconverter. Certainly, higher quality (typically higher priced) teleconverters will have less loss of IQ. The same is true with filters in front of the lens.

You'll also have less light coming through. Depending on the teleconverter, this may be a 1/2 stop up to 2 stops of light. Losing 2 stops could easily prevent autofocus mechanisms from operating correctly.

That said...The best option for more 'reach' is to get a lens with a longer focal length. That way, neither IQ nor light will be impaired. But as mentioned by others, photography is making an acceptable compromise. Sometimes, when the longest lens available to the photographer is 200mm and they want to take bird pictures, then a teleconverter is an economical compromise versus buying a $5000 lens to get some bird shots.

What it comes down to is this: is the cost benefit worth the loss of IQ and light?

As far as putting a tele on a prime lens such as a 35 or 50...are you kidding? 80mm and 100mm primes are readily available at quite reasonable prices, and there's no loss of IQ or aperture.

 

[SCraig]

Teleconverters have their place as long as the user understands that there is going to be a loss of image quality and light transmission through the device. Depending on the subject, the lens in use, and the quality of the TC the difference in image quality can be minor. Sometimes it is easier to stick a small teleconverter in my pocket than it is to carry two lenses but I do so knowing that I have to be careful when using it.

As BRAtkinson mentioned above, there are two drawbacks to a teleconverter: The loss of image quality and the loss of light transmission. Possibly three is you count the fact that you have an effective smaller aperture which, in turn, means a longer depth-of-field. High-quality devices will have much lower loss of image quality however the loss of light transmission is inherent in the device and there is nothing that can be done about it.

I have two; one is a 2x inexpensive model that is not worth using as a paper weight and the other is a 1.4x that works pretty well with some lenses when there is plenty of light.

In my experience they do tend to work better on shorter, faster lenses. My 1.4 works quite well on my 17-70 zoom, not as well on my 70-300 zoom, and is only occasionally useful on my 150-500 zoom. When I use it on my long lens it is always a question of whether the final image will look better cropped heavily without using the teleconverter or cropped less when the TC is used with the inherent loss of image quality. In most cases cropping heavily without the TC looks better however I have taken some shots that looked better using the TC and cropped less. I normally tend to shoot both ways and decide which works best when I get home.

 

[Overread]

SCraig I think the pattern you have there is that teleconverters work better on zoom lenses with a smaller divide between the focal lengths. They can work wonders on long prime lenses like 400mm f2.8 lenses - however when you've a a 7-300mm or 150-500mm you've got a huge amount of shift in the focal lengths within the lens itself - the lens is already going a little softer at its longest end before you add a teleconverter that magnifies those weaknesses.

Short lenses are not typically used with teleconverters for several reasons:

1) Its often easier and more affordable to get a longer lens - a 50mm with 2*TC is only a 100mm lens and most who want that all the time would just get a 100mm lens on its own.

2) Teleconverters have a protruding front element that sticks out into the back of the lens they are mounted to. As a result they can only fit to a certain selection of lenses. Most shorter focal length lenses tend to have very little recess or even push back into the camera a little and as a result simply can't be physically mounted to a teleconverter (Kenko pro series teleconverters have the smallest front protrusion, but its still there so you've still got to have the right lens to fit to it).

 

[SCraig]

SCraig I think the pattern you have there is that teleconverters work better on zoom lenses with a smaller divide between the focal lengths. They can work wonders on long prime lenses like 400mm f2.8 lenses - however when you've a a 7-300mm or 150-500mm you've got a huge amount of shift in the focal lengths within the lens itself - the lens is already going a little softer at its longest end before you add a teleconverter that magnifies those weaknesses....

You are probably right, which is why I stated "In my experience". The only prime lenses I own now are for my old Olympus OM2N 35mm body so I have no experience with primes on a DSLR. I will say that my 1.4TC works quite well on my 17-70 zoom though.

Also, I assume that you meant 70-300 lens in the first paragraph and not 7-300

 

[astroNikon]

I actually looked at TCs when I first bought my d7000 as a cheaper method to expand my lenses and telescope in a way.

But what I learned was that a TC (as mentioned above) is just not something that automatically provides 1.4x or 2x the focal length, but there are many tradeoffs that one takes. Of course, you also have to make sure that it would actually work with the lens and camera that you want to use it for. It's not a one size fits all piece of equipment.

After I got over my fascination of TCs I left well enough alone. Until now, when I thought it would be neat to get a 300mm f/4 and get a 1.4 or 2 TC for it. But that's just an idea again as some members have had good luck with extending their reach on long lenses.

 

[Braineack]

Isn't a 50mm 1.8D around ~$80-90 USD used? Why not just pick one up; you said yourself you enjoy manual focus. then when you decide you want autofocus, you can just buy a D7100.

 

[JacaRanda]

I have the 300mm F4 and the 1.4 TC. The heavy crop without TC vs. light crop with TC question is always in play as SCraig mentioned.

 

[hamlet]

Isn't a 50mm 1.8D around ~$80-90 USD used? Why not just pick one up; you said yourself you enjoy manual focus. then when you decide you want autofocus, you can just buy a D7100.

The D version optically inferior.

 

[raventepes]

Isn't a 50mm 1.8D around ~$80-90 USD used? Why not just pick one up; you said yourself you enjoy manual focus. then when you decide you want autofocus, you can just buy a D7100.

The D version optically inferior.

True, but a TC on a 35mm or 50mm is somewhat redundant. It'd be better to crop and resize, if need be.

 

[Braineack]

Isn't a 50mm 1.8D around ~$80-90 USD used? Why not just pick one up; you said yourself you enjoy manual focus. then when you decide you want autofocus, you can just buy a D7100.

The D version optically inferior.

OHHHHHH NOOOOOOOOOOOOOOOOOO!!!!!!!!!!!!!!!!!!!!!!

 

[o hey tyler]

Just get a Rokinon 85/1.4

 

[astroNikon]

Isn't a 50mm 1.8D around ~$80-90 USD used? Why not just pick one up; you said yourself you enjoy manual focus. then when you decide you want autofocus, you can just buy a D7100.

The D version optically inferior.

The AF-D lens are not optically inferior. matter of fact some older lenses still are fantastic to use. My 75-300 AF (no D) is a fantastically sharp lens at all focal lengths and predates the "D" functionality. There are some fantastic AI-S lenses (predates the "AF" features) and fully manual lenses out there too that are inexpensive but fantastic glass. And since you want to do things manually you should investigate pre "G" glass which has all the fancy AF-S auto focusing motors built in. Basically stuff you won't use but will pay alot of $$$ for that you don't use in Manual.


If you check this guy out, he has alot of AF-D and AI-S lenses in his best lens list
Nikon's 10 Best Lenses
FWIW, alot of people don't like these guys overall individual recommendations .. but that's something else to learn too.

 

[Mach0]

The AF-D lens are not optically inferior. matter of fact some older lenses still are fantastic to use. My 75-300 AF (no D) is a fantastically sharp lens at all focal lengths and predates the "D" functionality. There are some fantastic AI-S lenses (predates the "AF" features) and fully manual lenses out there too that are inexpensive but fantastic glass. And since you want to do things manually you should investigate pre "G" glass which has all the fancy AF-S auto focusing motors built in. Basically stuff you won't use but will pay alot of $$$ for that you don't use in Manual. If you check this guy out, he has alot of AF-D and AI-S lenses in his best lens list Nikon's 10 Best Lenses FWIW, alot of people don't like these guys overall individual recommendations .. but that's something else to learn too.

I think he was just referring to the 50 prime

 

[Braineack]

The AF-D lens are not optically inferior. matter of fact some older lenses still are fantastic to use. My 75-300 AF (no D) is a fantastically sharp lens at all focal lengths and predates the "D" functionality. There are some fantastic AI-S lenses (predates the "AF" features) and fully manual lenses out there too that are inexpensive but fantastic glass. And since you want to do things manually you should investigate pre "G" glass which has all the fancy AF-S auto focusing motors built in. Basically stuff you won't use but will pay alot of $$$ for that you don't use in Manual. If you check this guy out, he has alot of AF-D and AI-S lenses in his best lens list Nikon's 10 Best Lenses FWIW, alot of people don't like these guys overall individual recommendations .. but that's something else to learn too.

I think he was just referring to the 50 prime

Still; it's not optically "inferior". True, it might not perform on paper as well as the 50mm 1.8G at 1.8, but it's still VERY good glass and cheap as hell.

How about this: the 50mm 1.8D is optically superior than the 35mm 1.8G, produces better bokeh and with less distortion. And it will surely outperform a 35mm 1.8G with a 0.7 TC. So why consider the 35mm 1.8G at all?

Hamlet seems set on using manual focus, so this seems like a perfect alternative to the TC in consideration. You can pick these up all day long for under $90 USD. They are an incredible bargain for costerformance.