GH5 Big Glass vs Small Glass

[joe12south]

I don't think there is anything magical about ff glass. I know that the Rokinons aren't "good" lenses compared to a Milvus or even a Sigma Art series, but I still think this is relevant:

M43: Panasonic 25mm f/1.7

Nikon: Rokinon Cine 35mm T/1.5

The Rokinon flares more and has less contrast. Smoother bokeh. Both resolve all of the detail the sensor can handle. With a filter and/or work in post I could degrade the 25mm to mostly match. I could not do the same in reverse.

 

[Shirozina]

There is one big elephant that no one has mentioned... Increased flare causing lower contrast. Since the full frame lens projects a full frame sized circle, there is a lot of spill onto the sides of everything behind the lens mount. We've noted several times that you can get better results by flocking the inside of the adapter that you are using. Part of this goes away if you are using a focal reducer of some kind, but there are still minor issues with them as well. Any straight through adapter needs to be designed with proper light baffles or it needs to be flocked (prefer both when possible). Proper light baffles are not just a block cut to the size needed for the imager, there is a design that keeps the reflections to a minimum while absorbing those reflections.

And flocking goes both ways, that nice chrome plated lens mount will reflect a lot of light, the light that bounces off the imager, then hits the lens mount, and then comes back to the imager (over and over).

So make sure you flock it! The stuff is cheap and you can buy it from telescope manufacturing places online. Yes people are really grinding their own lenses for telescopes and building everything.

Well seeing as all lenses project a circular picture and the sensor crops out a rectangle from the middle they will all spill extraneous light onto the interior surfaces of the adapter. I have flocked early version Metabones adapters ( designed BTW to use full frame lenses on a full frame sensor) to good effect before they did it them selves and also flocked a Viltrox EF-M1. Self adhesive black velvet sheet is available cheaply from DIY shops although there is probably more effective stuff from specialists. Another approach if you are really concerned about this (or your classic 'big glass' is perhaps not the most flare resistant i.e Leica) then you can use a longer lens hood to block the non image forming light getting in in the first place. Although this may take away the 'big' look........

 

[Shirozina]

The Rokinon is not handling those point light sources very well at all. Are you sure the lens is clean as it's a pretty big difference for lenses with modern coatings. Very different lighting though with no daylight from the windows on the right so not exactly and A/B test.

 

[Bern Caughey]

I've since traded in the Nocticron for the Olympus 45mm f/1.2 Pro, a far superior optic.

Jon,

What difference are you seeing between Panasonic’s 42.5/1.2, & Olympus’ 45/1.2?

I have Panasonic’s 12/1.4 & 42.5/1.2, but prefer the focus rings on my Olympus 25/1.2 & 12-100/4. Have considered replacing Panasonic 42.5/1.2 with Olympus’ 45/1.2 if only so the primes would should share a common filter size, but that’s a minor consideration, & I’d hate to lose Dual IS 2.

 

[wwjd]

Joe, was that 25mm really at f1.7? Seems like there is a large difference in bokeh for 1.7 to 1.5, but I'm not a lens expert.

 

[OnSet]

Joe, was that 25mm really at f1.7? Seems like there is a large difference in bokeh for 1.7 to 1.5, but I'm not a lens expert.

Of course you also have two completely different lengths of lenses -- 25mm and 35mm. And one is f/stops - the other T/stops...

But the flaring is the obvious issue - along with the fact that the two lenses produce a vastly contrast different look. The difference is so pronounced that I certainly wouldn't want to use both of them for the same scene...

I guess it just got dark outside between the two shots...

 

[wwjd]

ah good point about mm, onset. I think to match those, ida dialed the 35mm down to t3-t4 ish. They get a lot sharper and would match the 25mm a lot closer especially on that chart. Not saying Roks are great by any means but they can look better than they do wide open.

 

[Bruce Foreman]

I have 2 Rokinon Cine DS lenses in Nikon mount, adapted to M4/3. The 24mm and 50mm (with focal reducers I can also get FF equivalents of appr 35mm and 70mm with them. I haven't had a chance to do intensive testing yet, but initial tests look good to me (and I have a fair collection of "native" optics also for comparison.

The #2 shot above shows more flare than I would allow with my lighting (but it's good to show how that lens can flare!). The flare from the bulbs in the background (and possibly from other source he has coming in from viewer's right to light the face) is really "contaminating" the center of the image and spreading some towards the edges. Now I'm using deeper hoods on my Rokinons because I work only in M4/3 and the lenses have a narrower field of view than when on a friend's Nikon. I'm temporarily using the one that came on the 50mm on the 24mm, and on the 50mm I have a rubber hood originally from Mamiya RB67 lenses.

My first tests were with the 24mm and I realize the lighting conditions and subject material make it a totally diffrent application from Joe's test, I'm not "knocking" what he's showing in any way. In the "snapshot" from a video test clip to see what this lens does at night, I am getting a bit of flare from some of the neons but it seems to be confined to a local area and is not contaminating to any objectionable degree. While not the equal of cine lenses costing many times the price of Rokinons, used carefully they are not bad optics.

The attached image is a "snapshot" from a video file shot with the 24mm Rokinon Cine DS T1.5, wide open and 1/60th sec at ISO 3200.

On the other hand, I find most "native" lenses to be a bit too sharp and am also testing some Tiffen Black Diffusion filters to find the strength that will "knock off" the edge on some of the sharpness.

 

[filmguy123]

I don't think there is anything magical about ff glass. I know that the Rokinons aren't "good" lenses compared to a Milvus or even a Sigma Art series, but I still think this is relevant:

M43: Panasonic 25mm f/1.7

Nikon: Rokinon Cine 35mm T/1.5

The Rokinon flares more and has less contrast. Smoother bokeh. Both resolve all of the detail the sensor can handle. With a filter and/or work in post I could degrade the 25mm to mostly match. I could not do the same in reverse.

Joe, can you "degrade" the native to look like the Rokinon Cine?

While the Rokinon Cine is ok, I think in comparison the m43 one looks digital and less appealing.

 

[joe12south]

Joe, can you "degrade" the native to look like the Rokinon Cine?

Yeah, mostly. A low con filter like the Black Pro Mist (or, hell, panty hose) can go a long way towards giving the Panasonic lens a similar look.

 

[joe12south]

Of course you also have two completely different lengths of lenses -- 25mm and 35mm. And one is f/stops - the other T/stops...

But the flaring is the obvious issue - along with the fact that the two lenses produce a vastly contrast different look. The difference is so pronounced that I certainly wouldn't want to use both of them for the same scene...

I guess it just got dark outside between the two shots...

Apologies if I seemed to imply that this was some sort of direct test. These just happened to be two set-ups I had handy from my Pocket 4K testing. There was no attempt to match. They are not only from different times of the day, they are from different days (note the different shirt and glasses.)

 

[joe12south]

Joe, was that 25mm really at f1.7? Seems like there is a large difference in bokeh for 1.7 to 1.5, but I'm not a lens expert.

Yeah, just double checked the metadata. Worth noting that the Rokinon is projecting through a Speedbooster, so that's also impacting the FOV and DOF.

 

[joe12south]

The Rokinon is not handling those point light sources very well at all. Are you sure the lens is clean as it's a pretty big difference for lenses with modern coatings. Very different lighting though with no daylight from the windows on the right so not exactly and A/B test.

Yup, that's what it looks like wide open. if you stop it down to 2.8 it will stop blooming and be tack sharp. In real world scenarios, I almost never open up the Rokinons beyond T/2.8, maybe T/2 if I have to.

 

[joe12south]

Just for fun, can anyone tell me if this is full-frame or MFT glass?

 

[brudney]

Looks like FF so it probably is m43

 

[filmguy123]

Yeah, mostly. A low con filter like the Black Pro Mist (or, hell, panty hose) can go a long way towards giving the Panasonic lens a similar look.

1. In post?
2. I find BPM changes the look a lot including light and highlight rendering. Similar is a vague term.

 

[filmguy123]

Just for fun, can anyone tell me if this is full-frame or MFT glass?

I think crops and even stills can often be deceiving. A 30 second cut with a dozen shots VS a 30 second cut with a dozen shots, but one FF and one native M43, gives a better impression of differences. And not in a studio setting, dropping the charts and perfect lights and staging.

 

[joe12south]

I think crops and even stills can often be deceiving. A 30 second cut with a dozen shots VS a 30 second cut with a dozen shots, but one FF and one native M43, gives a better impression of differences. And not in a studio setting, dropping the charts and perfect lights and staging.

Maybe, but I suspect if someone did that, we would find other reasons to object. The burden of proof is really on those that claim there is some visible advantage inherent in full frame glass. If they can't communicate it in either words or images, what is there to respond to?

 

[joe12south]

Looks like FF so it probably is m43

It's the wonderful Nocticron 42.5mm f/1.2. I'd put it up against ff glass.

 

[wwjd]

when we make images and films for normal viewers, NONE of them EVER notice, nor give a $#@!