Has any one bought one of these , I'm looking for hands on comments on the Mitakon Zhongyi Speedmaster 85mm F/1.2  lens, as I can't find any reviews.?

Its my goto concert lens.   This is a setting where autofocus is nearly useless.

 

It's really heavy.

 

I also have the Batis 85mm, but the difference in F/stop allows me to go much lower on ISO.

 

I had the Rokinon 85mm 1.4 and sold it soon after getting this.

 

I can link you to stills or video if interested. 

 

Did I say its heavy?

 

JCC

 

> > > JCC:

 

I have the Batis 85 mmm which I think is quite heavy @ 475 grams. You said the Mitakon is heavy. It weighs 900+ grams so it sounds plausible.

 

As you say, for concerts, autofocus may be nearly useless. Agree.

 

You said the Mitakon allows you to go much lower on ISO. Much lower? But there is theoretically only a one stop difference between 1.8 and 1.2 so I am disagreeing. But that is not what I am after.

 

The 1.8 and 1.2 values are calculated values. How much light actually comes through the lens depends on a number of things like coating, glass quantity and type of glass.

 

As you have both lenses, would you make me a favour and see what ISO values you get with the two lenses, both wide open, and all other factors equal. That would be a T-stop comparison rather than a f-stop comparison.

 

Thanks in advance.

If I understand your test correctly..

 

in a fairly dark room, same light for all tests

 

1.2 on A7S, 1/125 auto iso goes to 4000, at 1/250   8000

 

1.8 on A7S 1/125 auto iso goes to 5000, at 1/250   12800

 

1.2 on A7Rii 1/125 auto iso goes to 12800 at 1/250    52100

 

1.8 on A7Rii 1/125 auto iso goes to 32000 at 1/250   64000

 

John

 

Thank you for all these data! Before I make some comments, I would like to mention that as a long time analogue camera user I am quite familiar with shutter speed and other variations. And this in spite of my most used cameras were Leica Ms, a camera type judged by many to be the pinnacle of mechanical camera engineering.

 

Now to the data you so kindly provided, line by line:

 

Line 1. Absolutely normal; shutter speed is doubled and thus ISO is also doubled.

 

Line 2: Also normal, even if ISO is somewhat more than doubled but that may in effect be less than what it looks like as ISO values are shown in one-third stop steps. Well within limits.

 

Lines 1 and 2 compared: it seems Batis lets thru more light relatively speaking than the Speedmaster because the ISO does not go up from 4000 to 8000 (or from 8000 to 16000) when Batis is used rather than the Speedmaster. One would have expected ISO to double as there is a nominal one stop difference between Batis @1.8 and the Speedmaster @ 1.2. Zeiss lenses are well known for letting more of the light pass through the lens and hitting the sensor than some other manufacturers.

 

Line 3 and 4: I am at a loss why the ISO values measured with the A7r2 differ from those measured with the A7s, and also why on line 3 the ISO is quadrupled when the shutter speed is doubled.

 

Was the same Metering Mode (Multi, Center or Spot) used with both cameras?

Single shot AF, wide, multi for both cameras.

 

I had my eye to the viewfinder in all cases, so screen light was not a factor.

 

The A7S is much more sensitive to light.  Not only will the ISO setting go higher, it just handles the light better.

 

I'm going to do a second experiment, comparing both bodies with the same lens and exif setting.  I'll post both raws, but I'll do a separate topic for it. I can tell you already, the S will be much brighter.

 

John

Did you have exposure Value Compensation ON on one of the cameras, but not on the other?

 

I find it difficult to understand why the S ( images ? ? ? ) will be "much brighter" if it uses ISO 8.000 when the R uses 52.100

 

Looking forward to seeing your RAWs!

Its my goto concert lens.   This is a setting where autofocus is nearly useless.

 

It's really heavy.

 

I also have the Batis 85mm, but the difference in F/stop allows me to go much lower on ISO.

 

I had the Rokinon 85mm 1.4 and sold it soon after getting this.

 

I can link you to stills or video if interested. 

 

Did I say its heavy?

 

JCC

JCC thank you I assume from this you are happy with the IQ how easy is it to focus? 

I have found using old manual pentax lenses they are all sharp if focused spot on but some are much much easier to get on the sweet spot than others despite all of them being made as manual focus lenses.