APO extender image quality versus digital crop on M240

[Habbable]

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Hello All,

 

I've found this forum to provide great advice and perspective, but I haven't found too much information about the following.

 

I tried using a 2x apo extender (newer, rom version) with a 180 f/3.4 apo and a 280 f/4 apo R lens on a Leica m240 and am not getting very good results. Focusing is obviously tricky with the EVF, but looking at results taken on a tripod with the 2x extender, the images don't appear to be very sharp (on center).

 

Comparing the images with/without the extender (using the appropriate R-lens profile) seems to show that cropping the image is about the same, if not better than the 2x-apo extender. Perhaps I need to do additional adjustments (white balance?). Currently I am just refocusing when running the comparison and changing the shutter speed. In retrospect changing the aperture may be a better comparison...it is unclear to me whether the extender changes the f-stop (i.e. increases the DOF) or just reduces the light analogous to an effectively changed aperture.

 

Have any of you had better luck on an m240 with the 2x apo extender versus cropping the image?

 

Thanks!

[jip]

I believe the depth of field remains the same, because the F stop is reduced (not sure about this)

 

Of course accurate focus at a smaller F stop is more difficult, even with a EVF. I'd think the APO extender should do fine and deliver great results.

 

Maybe someone else with more experience knows better. 

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[jankap]

Perhaps an upload of (ev. cropped) pictures of your experiments would help.

I am happy with my 360mm f/6.3 (180mm 3.4 with APO-extender).

 

Don´t trust the depth of field markings. Please focus at the most important part. The part, that should be sharp.

The depth of field changes from 180mm 3.4 to 360mm 6.3 too. But the engraved marks are for film (thick layer), a sensor is more critical (flat surface).

Jan

Edited November 11, 2016 by jankap

[jaapv]

In my experience - I use both the 1.4xAPO and 2xAPO, I have even used both APO-Extenders stacked- the image quality is impeccable. I question Leica's advice to stop down one stop with the 2xAPO, I do not see the need.

If you are having a sharpness problem there must be a problem with the extender, I would have it checked for optical problems like decentering if i were you.

 

Additionally, if you are seeing unsharpness in the center of the image only and the edges are better it does mean that you are misfocusing. With the EVF this cannot happen, as the image in the viewfinder is exactly what the sensor captures and the focus assistance is in the center of the image. Focusing should be easy, as focus peaking should be very clear and precise with these combos, especially at 10x.

[ph.]

I have used the 2x apo (rom version) with the 80-200/4 (rom) the 100 apo macro (and the 60 macro on an MFT). No problems. I would examine other factors than the extender first if your pictures are unsatisfactory.

 

p.

[Habbable]

Thank you all for your comments. My impressions from previous posts supports the positive comments from those using APO extenders in this thread.

 

Here are some cropped images of a building at a distance taken from the raw files using the 280 f/4 APO lens. I tried focusing on the building sign using 10x with focus peaking, but it was hard to get clear peaking over large areas of the image with the 2x extender.

 

Here is a link to all of the files if you're interested: https://utexas.box.com/s/bz40v1dnk4yd80onavj3wa4ghtb0izz2

 

Thank you for your input!

 

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[Habbable]

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Here are the images using the 180 f/3.4 APO lens.

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[jaapv]

These lenses are of an age. Even if they appear to be quite clear, they are virtually certain to have developed a bit of haze over the years. I would advise you to have the lens elements cleaned by a competent technician. You may well be surprised at the difference this makes.

[Habbable]

Interesting...the 180 came back from a DAG CLA in May.

 

I recently purchased the 280. Under strong light it looks very clear, but maybe there is something subtle going on.

[michael_b]

On your pictures I can see that the characters are unsharp because of vibration. If you look in detail on the characters, you can see a second character which has a small offset to the original. Using the extender you have a high focal length. Even with a tripod you need to be careful, that the camera does not vibrate when taking the picture. Do you use the self timer? Is the tripod stiff enough?

 

Best regards

Michael

[jaapv]

If it was at DAG it will be fine. He is good at washing windows .

If you are checking the performance on the 180 APO  3.4 do so at infinity. It has some weaknesses at closer distances which will become visible through using an extender.

I would send the extender  for a clean first if you haven't done so already..

[Habbable]

I am using a gitzo tripod (series 2), which is probably at its limit in terms of weight. I am also using the self timer with LV off (after focusing). The pictures are taken pretty much at infinity.

 

I'm in a bind, timing wise, since I am traveling to Antarctica for 3 months next weekend and have until Monday/Tomorrow to decide on whether to return the extender.

I guess, my post should have asked if the results I am getting are typical or if users are typically getting better results (i.e. something seem off).

 

I may have to wait until next year to buy/test a different extender...

[jaapv]

To summarize: in my experience the 2x APO extender will not degrade the image quality of the 280-4.0 APO to any extent that is photographically significant, even wide open.

[jmahto]

Thank you all for your comments. My impressions from previous posts supports the positive comments from those using APO extenders in this thread.

 

Here are some cropped images of a building at a distance taken from the raw files using the 280 f/4 APO lens. I tried focusing on the building sign using 10x with focus peaking, but it was hard to get clear peaking over large areas of the image with the 2x extender.

 

Here is a link to all of the files if you're interested: https://utexas.box.com/s/bz40v1dnk4yd80onavj3wa4ghtb0izz2

 

Thank you for your input!

Looks like camera shake to me (for 2nd picture).

 

Another factor could be not able to do infinity focus wide open. I had this issue with my 80-200R at 200mm end. For infinity (more than couple of miles) I had to stop down to f8 so that DOF extends enough to infinity. Just to eliminate this from your test, try something closer.

[sls]

I use a recently refurbished 180 f/3,4 with 2x extender on a Sony a7r. 

 

It seems extremely sensitive to camera shake. On a safari I held it down on a bean bag and got some good results, slowest used was 1/320.

 

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[sls]

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Edited November 17, 2016 by sls

[tobey bilek]

Camera shake is a big problem when you get to 300 mm effective.  

 

I have only been able to control it with two tripods or mounting the lens solidly to the tripod and then using a third support  from camera to tripod leg.  

 

Keep the shutter speed up to 1/250 at least and prerelease the mirror with a short cable release or the device Leica sold for that purpose.  I have two left over.

 

You need a good solid tripod, not some amateur model.   Never raise the head with rising center column.      

[Markstade]

I use a recently refurbished 180 f/3,4 with 2x extender on a Sony a7r. 

 

It seems extremely sensitive to camera shake. On a safari I held it down on a bean bag and got some good results, slowest used was 1/320.

Looks very good, according to the Bokeh, it is even wide open! Large sensors are usually better, don't exploit tiny errors so much!

[dkCambridgeshire]

Try using the lenses at increasingly higher ISO settings; if sharpness improves at high ISO (faster shutter speed) then lower ISO unsharpness is likely due to vibration -  in which case use a more substantial  tripod / head. I've used the 280/4 with the APO extenders and not experienced any problems.

 

dunk

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[jmahto]

This morning I did some test with my new tripod and 400mm Telyt and 2xAPO extender (making it 800mm). My M240 is not with me that's why I did it with Nex-6. The results were perfect and I could see extra details due to 2XAPO that I didn't see earlier with only 400mm Telyt.

 

I tried to compile the results in the picture below. Note that it is pushing the limits. 4.5lb camer+lens on a sub 3lb tripod with 15sec exposure (it was way before dawn. You could still see illumination from street lamp).

 

My guess is that it worked because of "electronic front shutter" of Sony. M240 doesn't have that and will create some shake. You may need to switch off LV after focusing and use the heaviest tripod you have.

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