Home

Please support mflenses.com if you need any graphic related work order it from us, click on above banner to order!

SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

pentacon 135 28 m42 plus teleconverter, anyone? advice pls!
View previous topic :: View next topic  


PostPosted: Sun Oct 18, 2020 10:48 pm    Post subject: pentacon 135 28 m42 plus teleconverter, anyone? advice pls! Reply with quote

hi, i bought a cheap penatacon 135 m42 in bad shape but its ok now, im doing some cla and ok, now i want to see if its ok to put some teleconverter (cause its extremely sharp) and in my oly omd it convert to 500mm or something.

i can bought a cheap quantaray teleconverter 2x , anyone have this experience?

thanks!!! Like 1


PostPosted: Mon Oct 19, 2020 6:22 am    Post subject: 2X teleconverter Reply with quote

A 2X TC will cost you two stops of light and exaggerate any optical flaws in your 135. You might get sharper results from simply cropping images taken with the 135 alone.

But if the teleconverter is cheap, sure, give it a try. Experiment and have some fun. Smile

I have my own cheap, 2X TC and I use it regularly. But not for the added reach. Instead, I like the enhanced swirls and bubbles I get when I use it with my Helios 44-2 or 40-2 lenses.


PostPosted: Mon Oct 19, 2020 9:10 am    Post subject: Reply with quote

You could look for the Vivitar 2x Macro focussing teleconverter. That is a very good one with 7 elements. Will also turn any nifty fifty into a 1:1 macro.


PostPosted: Mon Oct 19, 2020 11:18 am    Post subject: Reply with quote

D1N0 wrote:
You could look for the Vivitar 2x Macro focussing teleconverter. That is a very good one with 7 elements. Will also turn any nifty fifty into a 1:1 macro.


Yes I had the same thought.
I have one branded Teleplus which is a 7 element with macro helicoid.
It is MultiCoated and is an excellent converter.
It may be the same one branded Vivitar.
T

On second thought, I am not altogether sure that these appeared in M42 mount.
All those that I have seen are in bayonet fitting mounts FD, Nikon, Minolta, PK etc


PostPosted: Mon Oct 19, 2020 11:47 am    Post subject: Reply with quote

Quote:
On second thought, I am not altogether sure that these appeared in M42 mount.
All those that I have seen are in bayonet fitting mounts FD, Nikon, Minolta, PK etc


i think if i get one i can adapt it

thanks for the tips! i give a try and i tell you later!!

thanks!!!


PostPosted: Mon Oct 19, 2020 1:24 pm    Post subject: Reply with quote

Alternatively you could also look for the Panagor auto Macro converter (probably made by Komine), The Vivitar was made by Kiron.
https://www.pentaxforums.com/accessoryreviews/panagor-auto-macro-converter.html K-mount is easy to convert to m42 with the right adapter. Looks like this: https://www.pentaxforums.com/accessoryreviews/pentax-mount-adapter-k.html


PostPosted: Mon Oct 19, 2020 5:52 pm    Post subject: Reply with quote

I just have a Pentacon 135mm F2.8 lens and two 7-element Komura Telemore II MC 2X teleconverters, which were among the best in their category at the time. I once tested the Pentacon 135mm with the Komura teleconverters with mixed results. My camera was a 24 MP full-frame Sony A99.

With the lens wide open, there was some gain in definition in the center, but at the edges, the curvature of the field and other aberrations made the image worse than that obtained by a simple cropping! Remember that a teleconverter is never optically perfect and introduces its own aberrations. This is especially true at the edges and corners of the image.

To find out if using a teleconverter with a given lens has any advantage, you need to answer the following question: who has better image definition, the lens or the camera sensor? If the lens outperforms the sensor, using a teleconverter is worthwhile. However, if the sensor outperforms the lens, a simple cropping is the best solution.

The performance of a sensor is given by its ability to define fine details of the image. The sensor's performance depends directly on the pixel pitch. The Sony A99 sensor has a 6 μm pixel pitch, with a corresponding theoretical definition of 82 lines/mm.

Olympus OM-D, in contrast, uses a 3.75 μm pixel pitch sensor, with a corresponding theoretical definition of 133 lines/mm what, I believe, is considerably higher than the definition of a Pentacon 135mm F2.8 lens. This means that a 2X teleconverter on an Olympus OM-D will bring no gain in definition. The result will be what is called an "empty magnification" and you will still lose 2-stop exposure.


PostPosted: Mon Oct 19, 2020 8:26 pm    Post subject: Reply with quote

Gerald wrote:
I just have a Pentacon 135mm F2.8 lens and two 7-element Komura Telemore II MC 2X teleconverters, which were among the best in their category at the time. I once tested the Pentacon 135mm with the Komura teleconverters with mixed results. My camera was a 24 MP full-frame Sony A99.

With the lens wide open, there was some gain in definition in the center, but at the edges, the curvature of the field and other aberrations made the image worse than that obtained by a simple cropping! Remember that a teleconverter is never optically perfect and introduces its own aberrations. This is especially true at the edges and corners of the image.

To find out if using a teleconverter with a given lens has any advantage, you need to answer the following question: who has better image definition, the lens or the camera sensor? If the lens outperforms the sensor, using a teleconverter is worthwhile. However, if the sensor outperforms the lens, a simple cropping is the best solution.

The performance of a sensor is given by its ability to define fine details of the image. The sensor's performance depends directly on the pixel pitch. The Sony A99 sensor has a 6 μm pixel pitch, with a corresponding theoretical definition of 82 lines/mm.

Olympus OM-D, in contrast, uses a 3.75 μm pixel pitch sensor, with a corresponding theoretical definition of 133 lines/mm what, I believe, is considerably higher than the definition of a Pentacon 135mm F2.8 lens. This means that a 2X teleconverter on an Olympus OM-D will bring no gain in definition. The result will be what is called an "empty magnification" and you will still lose 2-stop exposure.


Like 1 Like 1 Like 1 Like 1 Like 1