Blackmagic URSA Mini 4K vs 4.6K – How Good is the 4.6K?

URSA Mini 4K vs 4.6K

The Blackmagic URSA Mini 4.6K is a truly affordable cinema camera with impressive specs that houses Blackmagic’s newest sensor. When it was announced last year, Blackmagic Design once again won many filmmakers over. Now that the camera has started shipping, there are many positive, but also some negative voices. Let’s take a look at the guts of the 4K vs 4.6K Blackmagic URSA Mini cinema camera in our lab.

Comparison: Blackmagic URSA Mini 4K vs 4.6K

On the outside these two cameras look identical. Inside the body they probably also share most of the same innards. What really differentiates one from the other is mostly the sensor as far as we can tell. The 4K sensor on the Blackmagic URSA Mini 4K is the same that was used on the large URSA camera and on the Blackmagic Production Camera. The new 4.6K sensor is 15% larger and similar in size to the ARRI Alexa and Canon C300 mark II sensors.

We will focus on testing several aspects of sensor performance and evaluate the image quality. To make this review fair, we will also throw the popular Sony FS7 into the mix as an additional reference camera.

URSA Mini 4K vs 4.6K

A look at the Specs

Specs-wise these cameras are virtually identical. Both shoot up to 60fps in 4K. The main difference lies in their maximum resolution and sensor size. The fact that these cameras shoot in all flavours of the Apple ProRes codec, as well cinemaDNG RAW is their big plus. It is, in fact, an aspect where all Blackmagic cameras have an advantage over most other low-cost cinema cameras on the market.

Blackmagic URSA Mini 4K

  • Max Resolution: 4K (4000 x 2160)
  • Max Framerate 4K: 60fps
  • Max Framerate HD: 60fps
  • Log Gamma: Film Log
  • Sensor: Aps-C (21.12 x 11.88 mm)
  • Mount: Canon EF or PL
  • Codec Bitrate 4K: up to ProRes 444 XQ – 312.5 MB/s
  • Price: About $3000

Blackmagic URSA Mini 4.6K

  • Max Resolution: 4.6K (4608 x 2592)
  • Max Framerate 4K: 60fps
  • Max Framerate HD: 120fps (windowed)
  • Log Gamma: Film Log
  • Sensor: Super35 (25.34 x 14.25 mm)
  • Mount: Canon EF or PL
  • Codec Bitrate 4K: up to ProRes 444 XQ – 312.5 MB/s
  • Price: About $5000

Dynamic Range

A good dynamic range rating allows us to capture a larger range of shadows and highlights in high-contrast scenes, an important property when it comes to comparing the URSA Mini 4K vs 4.6K and one where a main difference will become apparent.

We’re testing with a DSC labs XYLA-21 transmissive test chart. For our dynamic range tests we use the Zeiss 50mm Cp2 macro lens (more on how we test HERE).

Our software measured about 12 stops of usable dynamic range on the Blackmagic URSA Mini 4.6K (RAW). This is very similar to the rating of the a7S II and C300 mark II.

[Update:] How we tested: We measured dynamic range using uncompressed RAW with an ISO of both 800 and 1600. We decoded the files in DaVinci Resolve 12.5 with BMD Film 4.6K Gamma applied. We also tested dynamic range with Apple ProRes 422 HQ and had the same results.

Here’s a screenshot of the dynamic range of a few popular cameras compared.

Blackmagic URSA Mini 4.6K Dynamic Range vs URSA Mini 4K vs Sony FS7 dynamic range

In comparison to the URSA Mini 4.6K, our software measured about 8.5 stops of usable dynamic range on the Blackmagic URSA Mini 4K (RAW). The Sony FS7 reaches 12.5 stops.

For each camera there are different reasons why the dynamic range is limited. The Sony FS7 image seems to become unstable in the lower stops due to processing. There is noise reduction which cancels out noise, but it’s also apparent that we quickly loose detail in the darker areas. The URSA Mini 4K simply doesn’t capture as much dynamic range as the other cameras. The URSA Mini 4.6K would have potential for more stops of range, but noise becomes stronger in the dark areas. Unfortunately there is a lot of pattern noise there, more than on the 4K, which makes darker areas of the image less usable.

Here is a shot of the darker steps (11, 12, 13 and 14). Step 13 and 14 were not counted as valid range by our software, because there is too much noise. See the same image with raised gamma for better viewing below.

Blackmagic URSA Mini 4.6K Pattern Noise

Blackmagic URSA Mini 4.6K – Pattern Noise in Dynamic Range Step 11, 12, 13 and 14.

Blackmagic URSA Mini 4.6K Pattern Noise with raised gamma

Blackmagic URSA Mini 4.6K – Pattern Noise with raised Gamma

ISO?

The Blackmagic URSA Mini cameras are not strong when it comes to low light performance. In comparison, the FS7 has a greater range in terms of ISO. On the URSA Mini 4K there are only three settings: 200, 400, and 800. The URSA Mini 4.6K goes up to ISO 1600.

In our tests we found that there is little difference in image quality when comparing all of the ISO speeds available on a single camera. It might seem so at first because the image gets brighter with higher ISOs, but in reality the lower ISO speeds merely cut off the image video range. In other words, the same image only gets coded differently at different ISO speeds, seemingly without any difference in processing whatsoever. That’s why we recommend to use the full video range in ProRes, in order to get the best color gradations.

This can be achieved by using ISO 400 or 800 on the URSA Mini 4K and ISO 800 or 1600 on the URSA Mini 4.6K. When exposing your image, though, make sure that you do not underexpose the image, as it will look brighter with the higher ISO setting (800 on 4K and 1600 on 4.6K). If you want the best quality, overexpose your image so you don’t get the noise from the darker areas into your shot, but be careful about highlight clipping. The lower ISO speeds (200 and 400 on the 4.6K) should be avoided.

[Update:] In order to get the most range out of our footage, Blackmagic recommends rating the cameras at their native ISO, which is 400 on the 4K, and 800 on the 4.6K, and then processing the RAW files using the latest version of DaVinci Resolve with BMD Film 4K and BMD Film 4.6K Gamma applied to the RAW decode. In RAW mode, ISO can be selected during the decoding process. We found that a setting of ISO 800 gives you the best starting point to grade.

Image Quality

In terms of image quality, the Blackmagic URSA Mini 4K and 4.6K are highly regarded due to their codecs. The following images were taken from URSA Mini RAW files, the Sony FS7 with its native codec and the Fuji XT-2 mirrorless camera with an external recorder:

Blackmagic URSA Mini 4.6K resolution quality

100% crops (except the 4.6K downscaled to 4K)

What we can clearly see here is that the Sony FS7 and Fujifilm X-T2 have a cleaner image when it comes to fine details. The URSA Mini 4.6K and 4K, on the other hand, show a little bit of a moire pattern on fine lines due to aliasing. The resolution of the Sony FS7 UHD image seems similar to that of the URSA 4.6K RAW image downscaled to 4K in terms of how much detail they resolve.

When we compare the Blackmagic URSA Mini 4K vs 4.6K we see that the URSA Mini 4.6K resolves more detail than the 4K. The same is true when we compare a recording in 4K resolution on the URSA Mini 4.6K, to a 4.6K image on the same camera.

But image quality is not a thing that is black and white. Here you can see how the different cameras treat a natural object, as opposed to test chart stars:

URSA Mini 4K vs 4.6K Image Quality

Contrast on all images above has been adjustedfor a rough match.

Interestingly the image coming from the Sony FS7 seem much softer. Add some sharpening to the FS7 image, though, and you will find that the image gets much closer to the way the URSA Mini images look. In conclusion, I would say that the codec of the FS7 is its weakest point, but the image looks cleaner than the one from the URSA Mini 4K and 4.6K. All in all, the URSA Mini 4K and 4.6K have a similar looking image, though the 4K wanders off into a slight green tint while the 4.6K looks more magenta. There is a certain amount of noise in the shadow areas on both cameras, and the image is slightly sharpened in-camera. But the look is very natural and colours are quite neutral.

[UPDATE:] Here is a version of only the Sony FS7 image, graded and sharpened to match the URSA Mini processed RAW images above. Here you can see that the detail is very similar, but also how the codec easily falls apart on some portions of the image. The image is more stable and ready to grade on the URSA Mini’s:

Sony FS7 image graded to match URSA Mini 4.6K

Sony FS7 image graded and post sharpened to match the URSA Mini 4.6K

Rolling Shutter

Some cameras, like the Sony a7S II, suffer from a severe rolling shutter effect, a phenomenon also referred to as “jello”. Unfortunately, the rolling shutter that we see on most CMOS sensor cameras is also present on the Blackmagic URSA Mini 4.6K and Sony FS7.

As we can see, the rolling shutter on the Blackmagic URSA Mini 4.6K is identical to the one we found on the Sony FS7. 11ms is an OK rating when it comes to rolling shutter. On most mirrorless cameras the effect is more severe. The Blackmagic URSA Mini 4K however gets the best rating, as it has a global shutter sensor that does not suffer from the rolling shutter effect at all.

Rolling Shutter on the Blackmagic URSA Mini 4K vs 4.6K

RAW vs ProRes

When comparing the codecs on the Blackmagic URSA Mini 4K vs 4.6K we found that ProRes generally gives us exceptional results. RAW is a very nice option and should in theory extends bit depth of your files to give you finer gradations. We did not test this. Dynamic range is not increased when using RAW, however.

[Update:] We have compared gradations on a RAW and ProRes file and we can confirm that RAW increases the bit depth. So if you want the best filmic look for heavy color grading, we recommend to use the RAW option on this camera.

Conclusion

It was truly interesting to take a closer look at the Blackmagic URSA Mini 4.6K in comparison to the URSA Mini 4K camera. We saw that the dynamic range of the URSA Mini 4.6K is similar to the FS7. It is a vast improvement over the URSA Mini 4K, which really lacked behind on this point. On the other hand, the URSA Mini 4K has a global shutter sensor and thus doesn’t suffer from rolling shutter effect at all.

In terms of image quality, the URSA Mini 4.6K delivers a really nice image with balanced colors and a natural look. The URSA Mini 4K clearly comes from the same family of sensors, but has a slight green tint. There is slight aliasing on both the 4K and 4.6K when we compare it to the FS7, though, and noise kicks in quickly if you are not careful. Both cameras are no lowlight wonders, but there is an improvement on the 4.6K. [UPDATE:] Also, the 4.6K can shoot up to 120fps in windowed HD.

ursa-mini-4k-vs-4-6k-sidebyside

The most striking argument for the Blackmagic URSA Mini 4.6K is clearly its dynamic range. It also has a sensor 20% larger in size and an extra of 0.6K in resolution, which most will deem marginal in a world of 4K, UHD or HD delivery.

If dynamic range is important to you, then the URSA Mini 4K probably does not have what you want. But besides this point, both these cameras are very similar. In our opinion, for those shooting in studios, there is no good reason to upgrade to the 4.6K at this time. Everyone else will probably welcome the extra filmic quality the URSA Mini 4.6K can achieve.

Would I consider shooting on the Blackmagic URSA Mini 4.6K? Absolutely yes. With its high bit depth and natural looking image it will deliver high quality 4K with a high codec quality. There are other good and comparable cameras, but when it comes to film aesthetics and if you put quality control issues aside, then there is not much that will take you this far at the low pricepoint of the 4.6K.

What is your experience with the Blackmagic URSA Mini 4K vs 4.6K? Let us know your opinion in the comments.

avatar
21 Comment threads
35 Thread replies
0 Followers
 
Most reacted comment
Hottest comment thread
27 Comment authors
Jamie LeJeuneNicola VerdiFrame FuryMatthew Carmody Recent comment authors
  Subscribe  
newest oldest most voted
Notify of
 Ioanes Sinderman
Member
Ioanes Sinderman

Ad specs: The URSA Mini 4.6 is capable of recording up to 120fps in HD (windowed mode)

 Markus Magnon
Member
Markus Magnon

Nice Article. But i do not trust those dynamic range charts. The A7S must be at 15 stops… but the image doesn’t look as good as the Blackmagic pocket camera with 13 stops. It would be nice if cinema5d shoot “real” images like a gas station at night or people instead of a chart and cotton yarn. And it would be nice to see the images in 4K resolution. About the yarn. There is alot of detail in the Ursa Mini4k image. More than in the 4,6 image. Its a different ISO but it seems a little bit out of… Read more »

 Oscar Stegland
Member

If anything, you should trust these charts much more than anything the camera companies say. Why? Because they actually look at the noise in the image and gives you a “usable dynamic range” number instead of a maximum fictional number that no one will ever actually recover from the image. When was the last time you heard of Red beating Arri when it comes to dynamic range? It has never happened. Still, Red specify the dragon /helium sensors as having a whole 2 more stops of dynamic range than what Arri specify for the AlevIII sensor. Arri, a opposed to… Read more »

 Brian Hallett
Member
Brian Hallett

I totally agree with you Oscar. All I say is test the dynamic range of the raw too. If you’re going to test the camera, test the whole camera.

 Oscar Stegland
Member

Sure, but judging by their comments it seems like they did test this but found no difference in performance and as such proceeded with ProRes. Ideally, a camera shouldn’t give you more dynamic range just because you’re shooting raw. From what I’ve gathered over on the BMCuser forums, most people seem to agree with this conclusion.

 Brian Hallett
Member
Brian Hallett

well, I reserve the right to be wrong. Maybe I am, which is fine. It’s not like these are terrible cameras. I just see so much more out of the raw processed through Resolve, which could be just my one’s color correcting skills. Hell, maybe my shitting shooting has made me a hell of a colorist :)

Kevin Douglas Carr
Guest

What’s the thinking behind the ISO recommendations? Native ISO for the 4K is 400 and 800 for 4.6K, yet you recommend their top ISOs of 800 and 1600.

James Barnett
Guest

I’m pretty sure you get the best DR performance at 800iso on the 4.6k. I wouldn’t use 1600 unless I could expose to the right in poor lighting conditions.

Naader Rizk
Guest

James Barnett gets it! If your going to spend the coin shoot for the 4.6k

Bart Snakenborg
Guest

They are only great in controlled conditions. Cinema and greenscreen for example

 Brian Hallett
Member
Brian Hallett

Not shooting raw on either of the Blackmagic cameras is a big miss here, especially with the 4.6K. The power of the URSA Mini 4.6K really comes through when shooting raw and processing through DaVinci Resolve. My testing, I have both the 4K and 4.6K, shows there is more dynamic range when shooting raw than ProRes with the 4.6K. And, I think the idea of exposing to the right on the 4.6K is not needed. The 4.6K is not like older Blackmagic cameras. Even Captain Hook says he doesn’t ETTR on the 4.6K.

Nathan Rice
Guest

My company bought a BMPC 4K. I was so excited ..I wanted to use BM for so long…unfortunately it’s riddled with issues. Not impressed with the sensor..heard the Ursa isn’t any better. Bought the A7S ii and loooove it!

Scott Zhang
Guest

I still stick with FullHD that is good enough for me 😂 (Truth is my computer cannot editing 4k or more lol)

Eduardo Gonzalez
Guest

Wait a second. The part that really stood out to me that I’ve never heard before is the 4.6 K can shoot 120 frames per second in for Jay even though it’s windowed. Is that true? Or are you talking about the big Ursa

Fred Lescano
Guest

It shoots 120 fps in HD windowed mode.

Eduardo Gonzalez
Guest

Ok that’s what I thought thanks.

tomi bommi
Member
tomi bommi

i enjoy the c5d camera test.
but one thing i notice is a strange color difference here –>
comment image
red on the fs7 example looks brown in my browser. my recommendation would be to give your site visiters a short test rollover to check if their browser is correctly color-managed.
as a resource on how to do this see the following link:
http://www.gballard.net/psd/go_live_page_profile/embeddedJPEGprofiles.html

thanks for your good work, tomi

Martino Vincenzi
Guest

The test explains very well why I love BM and not so much Sony: colorous are so bad in the orangish that the skintones are far from being any good or natural.

Dennis L. Sørensen
Guest

Hi Sebastian. Why do you recommend a stop higher ISO then native? It is not clear in the article?

Tim Naylor
Member

Great tests. Thanks. Could you elaborate on the recommended ISO’s? You say the BMC’s are not great at low light. But I’d consider 1600 ISO a low light sensitivity. What am I missing? Also, while I like the objective nature of your tests, I’d recommend adding real skin tone (a face) to them. Grading for flesh tone, IMO is the true test of a chip color science. Something the FS7 struggles with but you’d never know with your tests. What I do when A/B (or C) testing cameras, is shoot a face but with a color charts next to them.… Read more »

 Earl Thurston
Member
Earl Thurston

The “pattern noise” shown on the UM4.6K sample above is due to a recently discovered debayering imbalance. The issue is being discussed at length in a few forums, including the Blackmagic Forum under the topic “Cross Hatching Wont Go Away.” A side effect of this issue can cause moiré patterns, even in areas without any detail (e.g. out of focus areas or smooth surfaces) when the image is resized. Methods to eliminate the problem include adding a “BayerGreenSplit” value to the DNG’s through CornerFix or ExifTool, or using a 0.5 (half) pixel horizontal and vertical offset in Resolve or other… Read more »

James Barber
Member
James Barber

I agree, it’s really obvious with the blown-up crop with raised gamma. I wonder if this is throwing your software measuring the dynamic range, as to the eye it looks like at least 14 proper stops of range on the XYLA chart (stop 14&15 look like gravy stops), but the dynamic range looks remarkably close to the Alexa charts you have on other reviews.

I’d really put the alexa chart on this review so people can see how close it is by eye.

 Earl Thurston
Member
Earl Thurston

According to the URSA manual, the URSA Mini 4K can also record 120fps in 1920 x 1080 (windowed) mode, but only to ProRes HQ, 422, LT and Proxy formats.

 Frame Fury
Member
Frame Fury

Can confirm. I own the 4K and it shoots 120fps HD windowed.

Jamie LeJeune
Member
Jamie LeJeune

Based on the images you posted its clear that the 4.6K camera you were testing has a debayer problem that has been well documented on the BMD forums and appears to be affecting a high number of 4.6K units. The debayer issue could very likely be causing your testing software to report less dynamic range than a properly calibrated sensor actually has. BMD has been issuing RMAs for affected 4.6K cameras, though a few owners have reported that some support staff are still ignorant about the problem. For details please view these two threads on the BMD forums: https://forum.blackmagicdesign.com/viewtopic.php?f=2&t=50175 https://forum.blackmagicdesign.com/viewtopic.php?f=2&t=51936&hilit=yost… Read more »

 Nicola Verdi
Member
Nicola Verdi

Your should write more about this:

(Many renting houses give a WARNING)

WARNING:

We cannot recommend this product for professional work. We reached this decision after repeated failures in the field, experienced both first-hand by LR-folks and second-hand via rental clients. Though it might work much of the time, it is our opinion that this product’s performance is too unpredictable to be trusted on high-value projects. Use for casual testing or try-before-you-buy purposes only. If you have any questions, please contact us. [email protected] | 901-754-9100

Ben J
Member
Ben J

Good to see a review that acknowledges these image issues. I’d also like to see other areas of the 4.6k explored. When I hired it, I found the available mic amp gain very low and the gain controls hard to work with – no end stops, no feedback on screen. I was surprised by the handle, which felt plasticy. And, without the new 4.0 firmware, no easy way to adjust aperture while shooting handheld. But some great images to be had if you can get around the other challenges.

 Greg Greenhaw
Member

So did you shoot the dynamic range test in raw? The BM log profile is pretty contrasty and it bests baked into the prores. If you shoot raw you can pull out that data. The raw maybe appear the same in resolve at first glance but the data is there to be pulled back in. Also you want to make sure you working in

Daniel Joseph
Guest

Any data on the XT2’s dynamic range?

 Markus Magnon
Member
Markus Magnon

Ab bit offtopic. But are there any plans from cinema5d to test the BMMCC (Black Magic Micro Cinema Camera). Its only 1080p. But Global Shutter, 13 Stops Dynamic Range, 60 FPS, and only 1000,- Euros. Better Battery live than the Pocket. And all you have to do is buy a Speedbooster (another 700,- Euros) and some Monitor. Of course it was designed for drone. But they used this camera for POV Shootings in the latest “Jason Bourne” Movie. And Paul Thomas Anderson (Magnolia, there Will be blood) uses the pocket (similar 16mm sensor) for his documentary about Johnny Greenwood (Radiohead)… Read more »

Matthew Carmody
Member

I think you are spot on to mention the BMMCC.

The global shutter feature unfortunately never got included in the final camera.

Nevertheless, I own one and it is one of the best bang-for-buck cameras ever IMHO.

Great colors, great codec, great size and with a speedbooster it is almost (not quite) a S35 sensor shooting FHD raw at up to 60p.

Matched with the right lens it can easily be cut with Alexa, RED, or whatever expensive camera you want.

Check Mr CheesyCam for some rig tips as well.

Jamie LeJeune
Member
Jamie LeJeune

Have you gotten BMD to fix the crosshatch issues with your test camera? Are you planning to do a retest on a properly working 4.6K?

Member

Could you expand on the significance of global shutter and how much of an issue or limitation that presents to me practically as a filmmaker? If I were to purchase the Ursa mini 4.6K what kind of challenges and limitations would I face because of lack of global shutter?