[HarisF1]

I've read that the following lenses cannot be used:

• smc Pentax-DA 15mm F4 ED AL Limited
• HD Pentax-DA 15mm F4 ED AL Limited
• smc Pentax-DA 21mm F3.2 AL Limited
• HD Pentax-DA 21mm F3.2 AL Limited
• smc Pentax-DA 40mm F2.8 XS

And I've just plucked up the courage to buy a DA 20-40 lens... Has anyone used it with this TC? I know that the long end will be rather slow (around 55mm and f/5.6) but I'm interested in the potential use of the two. Are there any other lenses that also don't work well with this teleconverter?

Cheers!

[mechmike10]

As a general rule, wide angle lenses don't work well with TCs. The same for wide angle zooms. I'd be surprised if any of those you mention have acceptable IQ with any TC. Also, some lenses won't work with a TC because the rear lens elements will interfere with even mounting it on the TCs. If you can safely mount the 20-40 on the TC, I don't think you will care for the images the combination produces, especially at the wide end.

[Unregistered User 8]

Which lenses do not play well with the HD DA 1.4x TC?

The in-depth review on the forums does not recommend the use of the TC with wide angle lenses. Except for a couple of specific examples using the 50 & 55 with the TC for portrait lenses, most uses are for telephoto lenses for more reach. You have probably seen the review, but in case you have not, here it is. I have put the conclusion 1st as it has the " who's it for " section listed. Hope this helps.


Pentax-DA 1.4x AW AF Rear Converter Review - Conclusion | PentaxForums.com Reviews


PS. I own the HD DA 1.4x Rear converter and use it only on the 100mm 2.8 macro WR and the DA* 60-250. It needs to be used on quality glass as any issues with the lens get increased by 1.4x also. The 20-40 despite being high quality, is also quite slow at f4 at the 40 end.

[HarisF1]

Thanks for the heads up. I've probably read the review before but forgot about it. I guess there's no point going for a 28mm f/4 to 56mm f/5.6 lens. I could probably save more time just sticking my DA50 onto the camera.

Now I feel silly for starting this thread haha!

[UncleVanya]

I have both. I never thought about it since I'm usually carrying it with the 50-135 in the same bag.

[rawr]

Just for the benefit of future web browsers , the web page for the DA 1.4 rear converter features a big list of new and old Pentax lenses that it works with, or not.

[Unregistered User 8]

Just for the benefit of future web browsers , the web page for the DA 1.4 rear converter features a big list of new and old Pentax lenses that it works with, or not.

That is very helpful. Thanks mate.

[fsge]

Just for the benefit of future web browsers , the web page for the DA 1.4 rear converter features a big list of new and old Pentax lenses that it works with, or not.

Really helpful indeed!

[kh1234567890]

Just for the benefit of future web browsers , the web page for the DA 1.4 rear converter features a big list of new and old Pentax lenses that it works with, or not.

Just because a lens is physically compatible and the aperture of the combo is wide enough for AF to work does not necessarily mean that the resulting IQ will be any better than what you could get by a simple crop and rescale.

[rawr]

does not necessarily mean that the resulting IQ will be any better than what you could get by a simple crop and rescale.

Sure.

But resulting image quality largely depends on the optical quality of the lens and ditto for the TC.
Even better if the lens and TC were specifically designed to be paired together.

[kh1234567890]

But resulting image quality largely depends on the optical quality of the lens and ditto for the TC.

Not always. For example, the DA70 Ltd is good lens, but when I tried it with this TC the results were pretty awful.

[Driline]

Not always. For example, the DA70 Ltd is good lens, but when I tried it with this TC the results were pretty awful.

I thought TC's were supposed to be used with telephoto lenses. Why would you stick it on a short lens? Makes no sense.

[aslyfox]

I thought TC's were supposed to be used with telephoto lenses. Why would you stick it on a short lens? Makes no sense.

just cut and pasting from the review:

The teleconverter can also come in handy with shorter lenses. Say you're doing portraits with an FA50mm or a DA* 55mm F1.4 lens andneed to get closer. Use the rear converter and you now effectively have a 70mm F2.4 or a 77mm F2.4 lens, respectively. F2.4 still providesthat narrow depth of field which is often desired for portraits (as explained earlier in the review in order to get the expected F2 from an F1.4 lens with converter you must use a non-autofocus lens).
The rear converter is also an option if you need moremagnification for close-up photography. As an example it will provide 1.4x life-size magnification with a macro lenslike the smc Pentax-D FA 100mm Macro WR which by itself would only go to 1x magnification.


Read more at: Pentax-DA 1.4x AW AF Rear Converter Review - Conclusion | PentaxForums.com Reviews

[Sandy Hancock]

I missed the brief about the DA15 and DA21 not playing nicely.

DA15 + HD1.4xRC


Maritime history


Big City sunset

DA21 + HD1.4xRC


Darling Harbour, darling

Mind you, I only used these combinations as part of a deliberate challenge of using the teleconverter every day for a month. It's not something I would ever do in normal circumstances.

[HarisF1]

Did the combination not damage the TC/Lens?