Tag Archives: testing

Testing the Sony ILME-FX30

 

Please watch the video to see my video review or read on:

A few weeks ago I borrowed an FX3 from Sony for some testing in order to better understand the performance of this budget Cinema Line camera. I used it over a long weekend to shoot some circus acts and to perform some basic tests. By the end of the weekend of testing I decided to get one for myself even though I already own an FX3 and FX6. 

I shot various circus acts with the FX30.

 

So what made me buy the FX30?

For a start it’s cheap. At around $2000 for the body only you get a lot of camera for the money. If you want the same handle as the FX3 with XLR inputs, add another approx $500 to the base price. But as well as the low price I also I really like the fact that it is super 35 rather than full frame. The FX30’s 6K APSC sized sensor delivers really good oversampled 4K from a scan area very similar to super 35mm film. This means you can use it with almost any classic cinema lens, of which there are many to choose from. You can use it with zoom lenses designed for s35 (again which there are many to choose from) as well as lower cost APSC lenses.  A combination that I am particularly fond of is the FX30 plus the Sony 18-105mm f4 G APSC power zoom. While this combination isn’t ever going to win an award for the ultimate in image quality it is very reasonable.  It gives me great look images at a wide range of focal lengths in a surprisingly small package. 

But just how good is the image quality?

Sony advertise the FX6 and FX3 as having 15+ stops of dynamic range, while only claiming 14+ stops for the FX30. So one of the first tests that I did was to compare the dynamic range of both the FX6 and FX30 using my home made dynamic range tester. While this device isn’t necessarily ultra accurate, it is consistent and it allows me to visually compare the DR of the two cameras. I also thought it would be interesting to include the FS7, another s35 camera in my tests.

Dynamic range test to compare the FX30 to the FX6

As you can see from the above image, the dynamic range of the FX30 is extremely close to that of the FX6, so close in fact that I was unable to measure a difference with my home made tester. There is a 15th stop buried deep in the noise of both cameras and at 800 ISO the noise is very similar from both camera, if anything, visually I prefer the look of the very fine noise from the  FX30, probably a result of the 6K over sampling.

But what about compared to the FS7? In this image you can see how in the shadows the FS7 produces a lot of coloured chroma noise compared to the FX30. It is this chroma noise that makes it desirable to expose the FS7 a bit brighter than Sony’s base recommendation as it is quite distracting in lower exposures. So against the FS7, for me the FX30 is a clear winner in the dynamic range stakes.

Coloured noise in the shadows of the FS7 limit the useable shadow range compared to the FX30/FX3/FX6. In a video sequence the FS7’s noise is very obvious. Click on the image to enlarge it.

What about resolution?

OK, so the FX30 does not lack dynamic range, what about resolution, how does it compare with the FX6? To see this image larger please click on it. And be aware that scaling of the image that may be happening in your browser or computer and that scaling may add aliasing and moire to the images not in the original.

Comparing the resolution of the FX30 and the FX6. Click on the image to enlarge it.

 

What you can see from the above test is that aliasing starts to occur at a slightly lower resolution for the FX6 than the FX30. Aliasing happens when the resolution of the image falling on the sensor exceeds the  resolving power of the sensor.  This result isn’t really a surprise, the FX6 like the FX3 has a sensor that is a little over 4K pixels wide and it would appear that Sony tuned the optical filtering to squeeze as much resolution from this sensor as possible. Meanwhile the FX30 has a 6K pixel wide sensor, so it is easier to get close to 4K resolution without excessive aliasing. 

We can also see a difference in the coloured moire of these two cameras.

The FX6 produces more moire and aliasing than the FX30, click on the image to enlarge.

 

And I also chose to test the FS7 to see how much moire the FS7 produced. The FS7 was the worst of the 3 cameras by some way with a fair amount of strong coloured moire.

The FS7 produces more moire and aliasing than both the FX30 and the FS7, click on the image to enlarge.

 

I think what we are seeing here is simply improvements in the design of the Optical Low Pass Filter (OLPF) combined with the oversampled 6K sensor of the FX30 delivering an improvement in both resolution and moire/aliasing performance. The FX30 is a camera that is 8 years younger than the FS7, so you would hope that it would be better.

So, in the resolution stakes, the FX30 wins against the FS7, FX6 and FX3.

What about low light performance?

The FX30 has a Dual Base ISO sensor with 2 base ISO’s when shooting S-Log3 of 800 and 2500 ISO. The performance at these 2 ISO is very similar. The dynamic range is broadly the same and the noise is similar. But I would not say the noise is the same, there is more noise at 2500 than there is at 800, but not significantly more.

On the other hand the FX6 has a dual sensitivity sensor and its two base ISO’s are 800 and 12,800. This is a huge difference. You would need to add 24dB of gain to get from 800 ISO to 12,800 ISO and while the 12,800 base is noticeably noisier than the 800 ISO base, it is still quite useable. There is a small reduction in dynamic range at 12,800, but it isn’t really significant.

If you need to shoot in very, very low light the FX6 and FX3 are the clear winners, they are more sensitive than the FX30. But the FX30 isn’t as far behind as you might think. The 6K to 4K oversampling means the noise grain is very fine, so even with a bit of extra gain added in post production to bring it up to the equivalent of 12,800 ISO it doesn’t look terrible. It’s clearly not as good as the FX6, but if you needed to shoot in very low light the FX30 isn’t going to be a complete disaster.

First the FX6:

FX6 shot at 12,800.

And then the FX30, shot using the exact same light levels and exposure using 2500 ISO and then graded to match the FX6 which was at 12,800 ISO.

FX30 shot at 2500 ISO then graded to match the FX6. Same light level and exposure as the FX6.

 

I recommend you watch the video review to see these frames larger. There is more noise in the final FX30 image, but it’s not as far from the FX6 as you might imagine. But, on the sensitivity stakes, the FX6/FX3 are without doubt the winners.

What about colour matching?

A couple of quick tests, done both with S-Cinetone and S-Log3 confirmed what I expected I would find. As the FX30 is a part of Sony’s Cinema Line it looks pretty much like every other Cinema Line camera. The colours are extremely close to the FX6. It’s not totally identical, There are some very, very small differences. You do need to match the white balance of both as if you dial the same preset into both the colour temperature of each will be a little off, but once you find the matching white balance the images each produces will be close enough that only close side by side, like for like examination will reveal the subtle differences that do exist. I certainly have no concerns over using both the Fx30 and FX6 on the same shoot. 

What else do I need to know?

The FX30 does have more rolling shutter than the FX6, but it really isn’t terrible, it’s little different to the FS7. I suggest you watch the video and look at the circus footage that I shot with the FX30, rolling shutter didn’t cause me any issues.

The one thing that the FX30 does exhibit is a little bit of image smear. This occurs when you have a very bright highlight against a very dark background. What you get is a brightening of the background in line with the bright highlight. The FX6 isn’t totally smear free, but it’s very difficult to see the smear on the FX6, it’s not quite so hard to find it on the FX30. But for the vast majority of real world applications I doubt this will cause any major concerns, it certainly didn’t spoil any of my circus footage which often included very bright lights agains dark backgrounds.

FX30 CMOS smear (circled in yellow)

As you can see, even when looking for it, it isn’t always obvious.

In Conclusion.

Both practically and technically I really like the FX30. Mine will be used on my gimbal with the 18-105 zoom or handheld as a pocket sized camera (yeah, OK, a very big pocket). It has all the same codecs as the FX3 and it has breathing compensation, a fine step variable shutter (similar to ECS shutter) and you can use it as a very high quality webcam. It has the same CineEI modes as the FX3 plus an additional CineEI mode that allows you to add gain to the S-Log3 recordings.

Technically it performs really well. It has great DR and delivers a high resolution image with very well controlled aliasing and moire. Skin tones look great, full of subtle and fine textures. It’s plenty sensitive enough for most normal applications thanks to it’s two base ISO’s of 800 and 2500 (for S-Log3) and the colours extremely closely match those of the FX6, FX3 and FX9.

For the money, the FX30 is a lot of camera. 

Camera Test Charts To Print At Home

When testing and evaluating a camera, whether that’s a digital photo camera, video camera or digital cinema camera it is always useful to have a test chart or 2 (or more). While printing a chart at home isn’t always the best way to go, comercial charts can be very expensive to buy. So below is a link to an ISO 12233 chart, a Zone Plate chart and a Siemens Star chart that you can download  for free and print at home. You will need a good printer and good quality photo paper for the best results. 

For the ISO 12233 chart I divide this into quarters, print each 1/4 and then join them back together to make a larger chart.

The zone plate and siemens charts should be printed as large as possible, but in use they would not fill the frame, perhaps only a small part of the frame depending on the resolution of the camera you are evaluating.

I have not included any color charts or grey scale charts as it will be extremely difficult to know whether the colors or shades of grey your printer produces are actually correct, making the chart invalid.

Click on the green link or the images below:

Click here for ISO 12233 Test Chart as at the top of this page.

Zone plate derived from Imatest Software. Click on the image to go to full size file.
Siemens 100 radial star chart – click on the image to go to the full size file.