Teleconverters...Good or Bad?

proudgeek

Consider f/4.8 wide open for the purposes of sharpness. When you add a TC17, I would expect that shooting at f/4.8 would AT BEST give you same sharpness you get at f/2.8 (probably less, when you account for the TC).

sevencrossing

Mounting the TC it auto goes to 4.8. Is my lens physically stopped down to 4.8 exactly like without the TC with the same DOF and the same sharpness or is the lens producing the DOF/sharpness of 2.8 but displaying 4.8 because the camera accounts for the loss of light



the loss of light, is cause by increasing the focal length of the lens but not its diameter
An 120 - 340 f 2.8 zoom would be quite a big lens
dof changes with an increase in focal length
you will always get some loss of sharpness with a TC as it will magnify any defects in your lens
you will also get some loss of IQ as the light has to pass through more elements
loss of light because the light is passing through more elements will be minimal

http://en.wikipedia.org/wiki/F-number

Vipmediastar_JZ

I understand it now.

Day one was a challenge using it. Getting the Focus (focus hunting and locking) on the BIF and other subjects was not easy. I hope with more practice I can achieve great images because the reach is greatly appreciated.
Once I took off the TC I was able to instantly lock into the BIF

As far as sharpness goes I'm sure there is a loss in that department.

sevencrossing

Vipmediastar_JZ I think I have mentioned this on other threads
I do not believe the D800 + 70 -200f 2.8 + TC is the best of combinations
I have used my 80 -400 with success with peregrine falcons
As I am new to bif any failures are down to me, not the lens or my D800
Apart from theater work, I no longer use my 70 -200
the 80_400 is about the same size and weight as the 70m-200 f 2.8

Vipmediastar_JZ

I was using the DF 70-200 2.8 v2.
I haven't even tried it with the D800 but I can already see that will not be a great match.
I'll definately look into other options but if this doesn't satisfy I will make a sales rep a bit unhappy by returning it.

Msmoto

As I understand it, the reduction in f/stop is a result of the effective focal length being longer while the actual aperture opening is the same. And, as this is in effect actually magnifying the image from the original lens, the sharpness will always be less sharp.

However, as the larger image is now recorded on the sensor, the TC if working properly should produce a better IQ than simply cropping in post from the original lens image without the TC.

Folks have varied opinions due to experience and some TCs which are not of top quality.

Msmoto

Resurrection time for this thread.... just a couple images I think suggest that in some circumstances the teleconverters are very nice indeed.

With the D800E, 70-200mm f/2.8 VRII, TC-14EII. at 280mm, f/5.6, 1/320 sec, ISO 500



and a closer look:

Photobug

Those eyelashes are really sharp. Great job considering it was hand held and you had a big engine behind you vibrating the ground.

haroldp

I realize no one will have this yet
but I would be keen some samples of the new AF-S teleconverter TC-14E III taken with the amazing 80-400mm f/4.5-5.6G ED vr
my gut feeling is, you might see an improvement, over cropping , on a D4 but not on a D800E

I just finished fine tuning both the 80-400G and the 400/2.8 with tc14eIII, and it is noticeably better than the tc14-eII on both lenses both in resolution and contrast even in the center.
The 80-400 is very usable at 560 wide open and very good one stop down (f11).

The 400/2.8 is in a different league and excellent wide open (560/4), improving slightly further 1 stop down (560/5.6).

This new TC is well worth the cost in getting the best out of the lenses in front of it.

I now have to find some use for my TC14-eII.

.....H

haroldp

IMHO, both are clearly better than cropping, even on the D810 which I tested on.

....' h

heartyfisher

Read a review of the 3x teleconverter sometime ago(sorry forgot where). Was very surprised that it reviewed better than the 2x version. they were both Kenko Pro 300 Teleconverters .. but what lense would you put a 3x teleconverter on?

Golf007sd

@haroldp: Thank you for the feedback on the new TC-14 III. Looks like I know what I will add to my purchasing list on Black Friday.

Msmoto

I suppose all this means I need to grab a new TC-14EIII......just when I thought the EII was working ok....LOL

Golf007sd

@PitchBlack: Your point is valid; hence why I kept my D7000.

On the other hand, when using my 1.7 or 2.0E III, which mostly has been of surfers in action, available light is usually in great abundance, therefore, losing 1-2 stop's of light is worth the "price" in getting the additional reach...at the moment. In addition. from what I have been reading, by our members and other that have purchased the new 1.4E III, it performance is stellar.

Lastly, cost. Nikon D7100 (body only) $950 USD vs. Nikon TC 1.4E III $496 (USD). Think about that....

haroldp

I will say this again because I'm serious. The best teleconverter if you shoot full-frame is to buy a D7100. It's a 1.5x optically perfect teleconverter that loses you no stops of light. Think about it.

This is not entirely correct.

It assumes that the sensor outresolves the lens, which is still not true of the best lenses (such as Nikon 400/2.8 or 200/2).

It also assumes that the the TC is a simple and to some degree imperfect magnifier, which is not true of modern high end TC's.

Modern TC's (any current Nikon offering) form part of a complex optical formula which includes its own corrections.

This is why the tc-14eII has been measured at around 5% loss of resolution behind lenses like the 70-200/2.8, where a simple perfect magnifier would lose about 30%.

Similarly the tc-20eIII was measured at 26% where a simple magnifier would lose 50% (if it were perfect).

link to article is below.

https://photographylife.com/image-degradation-with-nikon-teleconverters

These tests were done with the 70-200/2.8 which is not nearly as friendly to TC's as long primes like the 400/2.8, because the TC's optical formula is a more predictable fit into a long prime, than a fast zoom, and it is likely that Nikon use the 400/2.8 as the design bench for their TC's based on this lens consistently behaving better with TC's than even their longer lenses.

My 70-200/2.8VR is not as TC 'friendly' as my 80-400G, but with the tc-14eII on a 12 mpx D700 (FX), it (70-200/2.8VR) clearly outperforms the bare lens on my D300 12mpx (DX). Having over twice the sensor area more than compensates for a 1 stop light loss.

My 80-400G bare is clearly better than My 70-200 with TC.

The 400/2.8 shows much less degradation with TC's than the 70-200/2.8, being quite good even wide open, though benefiting from 1 stop down,.

The 80-400G is in between, needing one stop down with the tc-14eII, but not more than that.

Shooting with (current Nikon) TC's on a D750/610 with lenses that work well with TC's will outperform a 24mpx D7100 bare lens in every way, with 36mpx D800/810, even more so.

The reason seasoned photogs like Thom Hogan use a D7100, is that even with the longest lenses and TC's, they still cannot fill even a DX frame, so more pixel density is beneficial and right now foe Nikon that is 24mpx DX. They never opt for less magnification on a smaller denser sensor unless portability matters more than IQ.

My tc-14eIII tests even better than the eII used above, but I have not yet used it for real photos.

Happy Holidays to all.

... H

haroldp

@pitchblack

The 200-400/4 is the least TC friendly Nikon long lens I have used except those that won;t work at all, and the The tc17eII on the 200-400 is the worst combination of TC and lens I have ever used.

If the combo you tried were the only one I had tried, I would reach the same conclusion that you did.

I no longer use, or even bother to focus tune TC's on my 200-400/4 and use other lenses when I need more reach. My 80-400G with a TC is better than my 200-400/4 with TC, but the 200-400/4 bare is clearly better at 400mm than the 80-400G, at least for my samples of these lenses.

All of these combo's must be focus tuned or they will not perform as they should.

If you have not done so, look into the RRS long lens support for the 200-400/4, it allowed it to perform like the super lens that it is.

Regards .... H

tc88

Modern TC's (any current Nikon offering) form part of a complex optical formula which includes its own corrections.

The correction is for correcting TC's own imperfection though.

This is why the tc-14eII has been measured at around 5% loss of resolution behind lenses like the 70-200/2.8, where a simple perfect magnifier would lose about 30%.

Sorry nothing can be better than perfect. A perfect optical magnifier should have 0% loss.

Personally I think it's a wash between achieving reach in DX or FX through TC. If the lens in front of the TC can resolve FX pixels, but not DX pixels, then putting TC behind it will degrade its FX resolution too. Or put it another way, if the lens has a resolution of 2 pixels, then putting a TC14 after it will make it to have a resolution of 2.8 pixels. Basically, information can not be introduced when there is none to begin with.

haroldp

@tc88

A perfect magnifier would spread the 'circle of confusion' of the base lens by the degree of its magnification, while adding none of it's own, resulting in a loss of resolution of at least 30 % for 1.4X.

A simple magnifier would also be located at the base lenses focal plane, which is physically impossible for the 1.4X as it is too short.

..... H

Photobug

I own the TC-17E and use it on the 70-200 F2.8 and happy with the results. Next year plan to add the Nikon 300 F4 (the 2.8 cost too much) and the TC-14E lll to my tool bag to use for both lens. Then I discovered that the TC-14E lll is not recommended for the Nikon 300 F/4 and the TC-17E is only recommended in bright light on the 300 F4 otherwise the D7100 AF system can't handle dim light auto focus with the 300 F4.

So my solution is to buy the TC-14E II for both lens. Kind of hurts that I can't take advantage of the improved image quality offered by the TC-14 lll. Am I missing something? Interested in hearing comments from those that upgraded from the TC-14 ll to the newer TC-14 III.

haroldp

@photobug
The tc-14eII is a very good TC and I was happy with it. The tc-14eIII is slightly but noticeably better on direct comparison of test images such as in AF tuning tests, but I would not worry about using the II for real photography, it is still excellent.

... H

proudgeek

I have shot the 300 f/2.8 with the TC14, 17, and 20. (the 17 was used with a D90, while the other two were used with the D800). I was pretty pleased with the results. Yes, there is some light falloff in the corners, but often I'm cropping a bit anyway so it rarely matters.

Photobug

Thanks @haroldp. That is excellent feedback. I have noticed that the older model price has dropped slightly at B&H.

@proudgeek - Also good feedback. Thanks.

heartyfisher

I am looking into a TC17. seems best compromise for IQ and aperture loss for my 70-200 F4. Anyone know if the TC17 is getting updated soon? some random post on the internet say it may be discontinued. @admin ?

Some reviews seem to like the TC2eiii more than the TC17eii any comments on that anyone?

Golf007sd

@heartyfisher: Having used both the TC 1.7 & 2E III on my 300 2.8, I can tell you the performance are both excellent in image quality. This is also true on the 105 2.8 & the 70-200 in relation to the 1.7eII. I have not had the chance to test them on my 200 f/2. With that said, when the lighting condition does change, I have noticed a slower response with the TC 2E III in AF locking in on the subject on my 300 2.8.

haroldp

The TC2eiii is slightly sharper than the TC17eii on my 400/2.8 despite the greater magnification.

Since getting the 80-400G I no longer put TC's on the 70-200/2.8, but the tc-17eII was disapointing on that lens, the tc-14eII was much better.

This could be my samples of these lenses and not typical.

... H