Minolta RF Rokkor 500mm/F8 & TCON on MFT

tb_a · Expire: 2019-08-28

I just wanted to reach the maximum magnification with my present gear and made some test shots of my mirror lens with different combinations on my Panasonic Lumix GF1 MFT camera which turns the 500mm lens automatically into 1000mm due to the crop factor of 2x.

1. The naked lens Minolta RF 500mm/F8 (1000mm FOV):

2. In combination with the Minolta M/A 2x Converter 1000mm (2000mm FOV):

3. Above combination added with the Minolta MD 2x Tele Converter 300-S 2000mm (4000mm FOV):

4. Picture of the 2000mm setup:

5. Picture of the scenery with 28mm FOV to give some impressions about the distance:

6. A comparison shot with the naked Tokina 600mm/F8 lens at F32 (1200mm FOV):

I must say that I am rather impressed by the reachable results. Though I have to admit that without the Manfrotto tele lens adapter it would have been impossible to do the pictures with more than the naked lens. This accessory turns out to be very helpful for such extreme situations. It is not very easy to find the correct focus even on such long distance shots. Luckily the GF1 has a very effective magnification functionality to assist correct focusing. All tele shots are done with the 10 sec. self timer to avoid camera shake. Focus was always set at the blue sign of the building.

All pictures are full frame, shot RAW and developed in LR6 with exposure and contrast adjustments. Re-sized for presentation.
The pictures of the setup and the 28mm view have been taken with the Ricoh GXR / GR Lens A12 28mm/F2.5.

hoanpham · Expire: 2015-01-18

Wow!! That are very nice results

iangreenhalgh1 · Expire: 2014-01-07

Would look better if not overexposed, try -0.5EV.

WNG555 · Joined: 18 Dec 2014 Posts: 784 Location: Arrid-Zone-A, USA

Fantastic clarity for stacking two teleconverters! The 28mm shot really put things into perspective.
I can't get acceptable results from one 2x on a Tamron 55BB. I'm considering attaching two elastics at each end to dampen oscillations and vibrations of the lens while on the tripod. Similar to that nylon strap on the manfrotto.

Lloydy · Expire: 2022-01-01

Very good, I like the MAnfrotto lens steady,and it obviously works.

tb_a · Expire: 2019-08-28

Thank you all.

Indeed it looks better if exposure is reduced a little bit. Obviously the LR6 auto exposure correction is somehow wrong. However can be easily corrected any time. - 2/3 EV seems to be optimal also for my taste.

It was more important for me to find out whether the overall quality is acceptable and I would rate it more than OK. The last time I used a similar combination for moon shots with film many years ago and it delivered acceptable results. Maybe I'll try this also on digital if the weather allows it.

The original Minolta converters are not bad at all also on digital and the RF 500mm is also quite capable if the focus is correct, which is the most difficult issue with this lens. That's at least proven. Luckily the weather was OK for such pictures. If it's too hot it doesn't work as could be seen in my last test shots with the Tokina 600mm lens in the far distance shots.

kds315* · Expire: 2021-03-09

Impressive and rather unexpected results Thomas! I do agree with Ian, it does look overexposed though
and 1/2 EV less would certainly do wonders to contrast and saturation.... Wink

tb_a · Expire: 2019-08-28

OK, manually exposure corrected (-2/3 EV):

I have to change the setup of LR6 somehow. This program always tends to overexpose pictures during conversion. Maybe there is a general setting to overcome this problem. I am not an expert in PP I have to admit. Alternatively I go back to JPG shooting. There this problem doesn't occur.

Also the picture from the GXR benefits from manual exposure correction. So it's definitely a LR6 issue.

tb_a · Expire: 2019-08-28

Out of curiosity I've tested the combination for a moon shot this morning.
Minolta RF 500/8 with Minolta 300S 2x Converter on Panasonic Lumix DMC-GX80 on Tripod; resulting in 2.000 mm FF-equivalence.
Picture downsized and converted to B/W.

RokkorDoctor · Expire: 2025-05-01

That's not bad at all.

I'm still under the dome of warm turbulent air surrounding the London area; a good sharp image of the moon is impossible from here on most days; there's almost always some "heat haze".

tb_a · Expire: 2019-08-28

Doc Sharptail · Joined: 23 Nov 2020 Posts: 1214 Location: Winnipeg Canada

I had tried with the Kiron MC-7 2X behind the Tamron 500 B f8 mirror on f/f with somewhat "mushy" success on Jupiter last fall.
Resolution was pretty dismal, but the color bands of the planet were surprising. I was shooting through live view as well (mirror up) and can't really account for the vibration, other than the big manfrotto tripod being somewhat springy with that much weight load being placed upon it. I think my exposure times were probably a bit long for what I was trying to do in the first place.

I'll probably try again in April, or later. There's either fog or ice crystals right now, and it will have to wait. A sighting tube would probably make it a bit easier with a combination that long.

Edit to add:

For those experienced with focal lengths this long, is a lens tripod foot any steadier than using the tripod socket on the camera body? The device pictured above with the lens tied to the tripod mounting has me really wondering now, especially since I still have the tripod collar for the 500 B.

-D.S.

tb_a · Expire: 2019-08-28