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Resolution test: Minolta MD 2x Tele Converter 300-s vs primes MD

This converter isn’t the lens, that’s why I don’t make a review of it. All these aberrations tests, bokeh, etc. were skipped. Additionally, review by Benjamin is totally enough for an understanding of 2x Tele-Converter 300-s and I can’t add something new, except maybe a few resolution comparisons.

After getting a new lens, I always take a few technical shots to understand its strengths and weaknesses – usually, it helps me a lot to start using an unknown lens with much less of doubt. One day I decided that my data might be interesting for someone else and this site has been made.

Minolta New-MD (MD III) 2x Tele-Converter 300-s parameters: index 297
Name engraved on lens MD 2x TELE CONVERTER 300-S
Lens design [el.] 7
Lens design [gr.] 6
Dimension Ø x length [mm] 65.5×41.5
Weight[g] 210
Year 1981
Style MD III
Code No. (ROKKOR-X) or Order No. 3579-807

Lens exterior:

(Please, forgive me the dust on the item, I never have the patience to clean objects for close-up photo sessions)

Test description: Camera Sony A7II (24mpx, full frame) – fixed on the tripod. Targets (buildings) – fixed by gravity power on the distances in more than 200 meters. All shots were made with apertures from fully opened and up to F16. ISO-100. Shutter Speed – depends on light (camera A-mode), WB – same for all shots. SteadyShot – OFF. The focus was manually corrected for each shot to exclude focus-shift affecting. Focus point – the center of the picture.

Finally, pictures were converted from ARW-files in Capture One with default settings, cropped for 300×200 px elements, combined into diagrams and exported into JPEG-files.

Note: I am just a man, I do not pretend that in all cases my focus settings were absolutely accurate. But I aspired to it.

I decided not to mix samples from different lenses and converter on one diagram as I do it usually for lens battles. In this case, such an approach can confuse. Therefore, for comparison, I recommend opening two charts in different tabs and switching between.

Very Important (!): I didn’t add any recalculations for diagrams. Apertures have been written down on sample pictures as they displayed on lenses. It needs to be kept in mind.  So in the case for example on F 1:4 – shutter speed with adapter was 1/150 and without adapter – 1/800.

Resolution – long distance, comparison #1:

Minolta MD 24mm F2.8 + Minolta MD 2x Tele-Converter 300-s 


Minolta MD 50mm F1.4

Resolution – long distance, comparison #2:

Minolta MD 50mm F1.4 + Minolta MD 2x Tele-Converter 300-s


Minolta MD 100mm F2.5

Resolution – long distance, comparison #3:

Minolta MD 100mm F2.5 + Minolta MD 2x Tele-Converter 300-s


Minolta MD 200mm F2.8

(samples look not good – I think it happened because strong wind, my mistake – using a lightweight tripod, but I left results as is because of it enough for an understanding of the main idea)

My conclusion:

I have never been interested in using such items because of the impact on sharpness. But after I got test-results my opinion about the converters has changed partly. I still don’t plan to use it, but the affecting of a resolution isn’t so dramatic as I expected. Anyway, the user needs to keep in mind other effects like increasing exposure time, DOF, bokeh, etc. It’s hard for me to imagine the good case for using this converter. Maybe it can help if a photographer is going to mountains and needs to save every gram in his backpack. And he is ready to take photos of mountains landscapes with poor sharpness… I don’t know.  So, my conclusion: instead of buying off this converter it would be better to get cheap MD lenses with needed focus distances. Yes, the converter works, not bad at least, but has no meaning for today.


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