TC Musings
 

My normal telephoto setup is a Canon 300mm f4 IS plus the option to add a Canon 1.4 TC. The raw lens gives very good results and adding the 1.4 TC still gives very acceptable images. For sometime I've had an itch that needed scatching to see how well a 2.0 TC would work. My local photography shop had a Canon x2 instock and I could not resist the temptation anymore. I bought it on condition if it was a flop I could return it. Needless to say I returned it the next day. But I had it long enough to do a quick and dirty test. Shots of a sawn tree stump but alas the wind was starting gust. However I have posted for your amusement.

1) Raw lens
2) 1.4 TC
3) 2.0 TC
4) 1.4 + 2.0 stacked
5) first image upsized in PS by 2.8 to compare against fourth image.

dragging off image 1 and progressively enlarging it to compare it alongside 2-4, it looks as if you are better off doing a more severe crop from just the basic lens. The converters appear to introduce chromatic abberation without any more detail.

Or isn't that what I am supposed to say/find?

If it is you have saved me another £140-180 (temptation, no money anyway) getting TCs for my Sigma 50-150

Very interesting Rob. I hope you don't mind but I have increased the first one by 1.4x to compare with the second. The left picture is your first increased and the right the one with the 1.4x TC

It would appear that the 1.4x doesn't do much either. I have a 1.4x so will carry out some further tests when I have time.

Dave

A good thread subject Rob as this is something a lot of people think of to increase focal length on a budget.

I found similar results when using a 2x with the 80-200, and that was a sharp lens when used on its own, hence the reason for swapping it for a straight 400mm.

Rubbish weather this week so I have time to think of a target as I don't have a sawn log end handy. Then I will see if I can post some comparison shots with mine and a couple of lenses.

Don

I thought I ought to post a link to Andys site with some TC info http://www.digiscoped.com/teleconverters.html

Don

This one has me hooked. I couldn't wait to have a try.

Here I was using a 200mm EF 2.8L lens with and without a 1.4x TC (Canon).

The left picture is just the 200mm lens but the image enlarged in PSPX by a factor of 1.4 and the right image is with the 1.4 TC.

Anyone want to buy a TC? Perhaps I will do some more tests before I do that, but it looks as if money could have been saved here.

Dave

I should add, they are both 100% crops.

Teleconverters tend to work better with some focal lengths and some lenses than others. I suspect the Canon ones are optimised for use with long lenses, and that the 200mm lens is ill matched. That is consistent with the fantastic results Andy (and others) get with a TC and a 600mm lens. Nikon even had two teleconverters, one for long lenses, and the other for not so long lenses.

Another link on the subject, although these are comments on Nikon converters. http://www.naturfotograf.com/index2.html

Click on lenses on the left hand index, then scroll down to the bottom of the page for Teleconverters.

Don

I will have a go when the hail, sleet and snow packs up. :p

Don

Thank you for that Leif. I will next test it with my 100-400 lens.

Dave

I regularly work with a TC14E on my Nikon 500 f4 AFS and can honestly say I can't tell the difference. I'm sure Leif is right, some converters only work well with specific lenses, on the other hand I have a Tamron 1.4 that seems to work well on my Tokina 150-500 f5.6 ATX, my Tokina 80-400 ATX and on my Tamron 90mm Macro. I think if you push the boat out and use a 2X converter on any lens, then you are going to have to except lower quality results. Having said that, if it's the only way you can obtain the shot, then the result is as good as it gets!

nirofo.

They also work best on primes, not zooms ... sorry to rain on your parade.

That's why I tried it on my 200mm lens first.
I've now tried it out with my 100-400 set on 400 and similarly to before the left picture is 400mm alone but enlarged by a factor of 1.4 and resaved. The right picture is 400mm + 1.4x TC, both 100% crops and other than cropping or enlarging unprocessed.

I am now much happier:)

I've enjoyed doing the tests and have learnt much. I look forward to seeing anyone elses tests.

Dave

Results using a 1.4x Zuiko with the Olympus [Zuiko] 50-200mm f2.8/3.5 are quite impressive - I'm thinking this might be the one bit of kit I add this year - mind you, they should be good at around £300 new!

As converters will multiply the effect of lack of resolution ( lens softness ) I had intended to do a comparison between 105mm AIS, the 105mm end of 28-105 Nikon zoom, and the 105mm setting on Stevies 28-200 Sigma, as my starter. Weather conditions here have not permitted that.

However I did spot a Hare in the field so did some comparisons using it.

The converter in use is Nikon TC201 2x and this is recommended for lenses of 200mm and below. Prime lenses used are Nikon 200mm f4 AIS and Nikon 400mm f5.6 AIS. These are all designs from the 1980's so are not a reflection of the current range in terms of performance.

I think this shows that although the TC201 is recommended for shorter focal lengths it gives a better performance on the 400.

Images attatched.

1) Full frame at 200mm to put the exercise in perspective.
2) Composite of crops using 200mm, 400mm and 2x converter.
3) Composite of 400mm crops showing the effect of adding sharpening.

Don

I managed an old style test today. No newspaper so I set up an old product leaflet and took the attached pics at a distance of 20 feet.

Lenses used : Nikon 105mm f2.5 AIS, and Sigma 28-200 f3.5-4.5 Ashperical IF zoom. Nikon TC201 2x converter

Lens aperture was f8 for all shots to give the zoom a realistic chance for image quality. Ideally this lens should be at f11 for best performance. Light levels did not allow f11.

Pics attached

1) A crop of the field of view showing the whole target.
2) Composites of 100% crops at 105mm
3) Composites of 100% crops with converter
4) Composites of the Linhof logo at 105mm and with the converter.

Don

One thing this test does prove is that the old Nikon 105 is still a terrific lens, far better than the new 105 AF. The Sigma doesn't even come close in this test.

The thing I could never understand was, why do you need autofocus on a macro lens?

nirofo.

It certainly shows the value of matching the converter to the lens - the 105 + 2x is very good at F8, though,obviously this makes it F16 in real life. Does the quality hold up at wider apertures, Don?

Now, anybody got a TC301 for Don to see what that 400mm can really do!

Adey,

I thought I would give your mission a go today. Two fresh thought into the melting pot.

1) When deciding a suitable distance last time, I initially tried 14 feet. Without a TC on, my Nikon 28-105 outperformed the fixed 105. :eek: Moving to a distance of 20 feet soon sorted that one out. :D The 105 is therefore happier at 20ft to infinity as at those ranges it outperforms the zoom.

2) I have used the TC for close ups with tubes and 55 micro very successfuly.

In view of the above I therefore decided that for your various aperture test to move the subject out from 20 feet to 35 feet. Composites attatched that show that at that distance the TC performance fell apart. Shed loads of CA at f4 so no point in going wider.

I did the 400 with and without, at 40 feet and the attatched are processed crops. In view of the 105 and distance experience, and as the sun is due to return next week, I will then try the 400 and TC at longer distances.

Pics attatched
1) Todays test target
2) Comparison at 20 feet and 35 feet using 105 plus converter
3) Aperture comparisons at 35 feet using 105mm and converter
4) 400mm at f5.6 at 40 feet - processed crop
5) 400mm and converter at f5.6 and 40 feet - processed crop

Don

So that users can try auto-focus, find out that it is useless for macro work, and hence not spend ages complaining they wish they'd bought an AF lens? Seriously though, probably because these lenses also make good portrait lenses, and perhaps AF is useful then. (Timid subject runs away but is caught in sharp focus by modern technology.)

Have you tried a 2x TC on your 500mm lens? Andy has some results with a 600mm F4 + 2x TC that are surprisingly good. And Arthur Morris has some in his bird book that are also surprisingly good. At least one of his pictures stacks TCs i.e. 1.4x + 2x.

I think we also need to remember that most of us are testing teleconverters on APS cameras. That means that any edge softness is going to be reduced. That said, I've tried a TC14A on a Nikon 75-150 F3.5, a Nikon 200mm F4 AFD micro lens and a Sigma 400mm F5.5 APO Macro, and the less said the better. The best of the bunch is the 75-150 zoom + TC which is surprisingly sharp, but CA is excessive. The TC14A is said to be for lenses less than 200mm so maybe that explains the results.

Well, I must say that I'm impressed with the 400mm + converter at F5.6, though I suppose the dimmer viewfinder image makes it less easy to use with a moving subject.

The key seems to be in finding the lens' best focus distance as well as aperture.

Things are getting trickier by the moment. :rolleyes: Still without this thread I would not have checked this aspect out at all.

As for viewfinder brightness you are right. Luckily the X has a lot brighter one than the D100, but it would a problem in low contrast/lower light level situation.

Don.

Surely you can use the focus confirmation light? That would be auto-focus with a DH motor I guess.

I've taken many excellent sharp photo's on my Nikkor 500 f4 AFS with a TC20E, however they still don't have the crisp bite of the 500 f4 plus TC14E combo. I've also obtained similar results using a Tokina 150-500 f5.6 ATX and a TelePlus 2X converter at 500mm (1000mm effective). Having said that, both lenses are of exceptional quality and among the best in their class. There are times when everthing is right and all things come together that you can obtain photo's which are way above the quality you could expect from the equipment being used. One particular instance I remember was when photographing Short-eared Owls, I was working from a hide, Olympus OM1n, Tamron 60-300 f5.6 SP at 300mm f8, Hoya 2X converter (600mm f16 effective) Kodachrome 64 slide film, Sunpak GT32 flash unit set up off camera outside hide. Here's one of the resulting photo's.

nirofo.

Very impressive it is too.

Don

On a reasonably bright overcast day like yesterday with light around EV14, then centre focus confirmation light does not display with 2x tc on, light levels reaching the a/f sensor are equal to trying to auto focus an f11 lens. :eek: The focus direction arrows work fine at these lower EV though.

Today with the cloud, the light level is EV11 and the centre confirmation light is out with the 400 on its own.

A/F would be very nice but pricey. Guess that would rate a thread, but then again, perhaps not. I must be one of the few here, or possibly the only one, using M/F at the long end. :rolleyes: :D

Don

don't you guys use tripods?? :D

:D :D

Pick 'n mix. :p

Don

I use a tripod 90% of the time for landscapes, wildlife, close-ups and general photography, I use a custom made ledge and bean bag from the car window 8% of the time for birds and wildlife and I handhold my camera 2% of the time, mostly flight shots of birds. I must admit though that very occasionally, very occasionally I might add, I take a hurried handheld shot of a particular scenic view, where the lighting is just right and I don't have time to set up for it. Unfortunately it's very rare I get a winner from it.

nirofo.

Uniloc 1600 + Markins M10, or bean bag for me.