Where does it matter and what do you gain: APS-C, Full Frame, Medium Format

APS-C vs Full Frame. Sensor size and what is promised.

I had been surfing around youtube recently and saw some interesting videos/comments on things like ISO, sensor size, equivalence  and so on. Some companies claim APS-C will give a smaller lighter package, others argue that if we look at the the equivalence, there is no advantage and in-fact full frame is better. But is that true? Does a full frame truly have 2x more light? Does a 17-50 f2.8 really equal to just a 24-70 F4? Is it true that APS-C is pointless since it doesn’t save any weight?

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Fujifilm GFX 50s with 250mm F4 and XT2 with 200mm F2

As you can see in the above, a APS-C can be larger and heavier then a medium format. So weight saving is a very subjective thing. Below we dive deeper into the sensor, equivalence and weight.

APS-C is smaller then Full Frame in area.
APS-C is smaller then Full Frame in area.

First lets look at the argument

A image taken by a 50mm F2 on an APS-C will look similar to 75mm F2.8 (or F3) on a Full Frame. There is probably not much debate on the looks and output on the photo. Where the argument lies is when companies market a APS-C lens and claims it saves weight when compared to a Full Frame similar lens.

Case in point, Fuji 16-55mm F2.8 vs 24-70mm F2.8. Definitely the Fuji APS-C version is smaller and lighter by about 300+g.  The Full Frame camp will argue that it is not equal and that a 24-70mm F4 is more comparable. The APS-C side will then counter that  a 16-55mm F2.8 is longer (approx 24-83mm) and you still get F2.8 in terms of light. This is where things turn ugly, people will start arguing that Full Frame takes in twice as much light and thus produce better image quality and bokeh. We will not touch on Bokeh since a Full Frame F2.8 is definitely better in that aspect. For this write up, lets look at exposure, weight and image quality.

In exposure there are 3 parameters, Shutter Speed, ISO, Aperture. Aperture is usually based on the 35mm standard and talks about how much light is let in by the lens. Shutter on the other hand is how much light is let in capped by the set duration.

Returning back to the lens, a F2.8 will always result in a F2.8 shutter. The 16-55mm F2.8 can take an image at 70mm with a shutter of 1/100 while a full frame equivalent in looks, which is about F4, will need 1/50 of a shutter. The fact remains that a F2.8 lens is always faster then a F4, even if they look similar due to difference in sensor size. But where does the extra light and sensor area go to?

D850 vs D500 Dynamic Range
D850 vs D500 Dynamic Range from Photons to Photo

What this chart shows is the dynamic range: the amount of information captured and thus usable. This affects us greatly when we do stuff like pull shadows and recover highlights for those crazy demonstration of black image to full colored +5 exposure.

So if we look at the chart above using the same company (cause everyone defines their own ISO) camera, you will notice that the D500 Dynamic Range at ISO100 is the same as D850 at ISO 165. So a full frame with 1 stop of ISO boost is the same as an APS-C at base.

So with this in mind, revisiting the lens, a 16-55mm F2.8 gives you faster shutter speed then a F4 equivalent. All the full frame camera need to do is raise their ISO by 1 stop and it equals out. In-fact it will be close to totally equaling out including image quality and whatever advantage a full frame sensor is suppose to have. So yes mounting a F4 version of the 24-70mm on a full frame essentially makes it the same as an APS-C 16-55mm F2.8.

We have gotten quality out of the way, let us look at the weight. We take the Sony A7m3 with the 24-70mm F4 vs the Fuji XT3 + 16-55mm F2.8. It is not exactly equal since the Fuji version does zoom in almost 15% more (70mm vs 83mm)

Sony: 650g + 426g = 1076g

Fuji: 539g + 655g = 1194g

Now its quite clear the XT-3 combination is heavier. It weighs some 120g more but gives you 15% more zoom. But wait, the A7m3 is the lightest Full Frame around however the XT3 is probably some of the heaviest of its type. Let us use the XT30, which for most works and outputs the same as a XT3 except for a smaller body and less buttons.

Fuji: 380g + 655g = 1035g.

Now we can go even further with some of the other bodies in the X series but you should get my point. APS-C body can get smaller then a Full Frame. At least no maker has made a lighter full frame then a APS-C ever was. So as a set of camera and lens, APS-C will be lighter. Just for a comparison to the lightest setup you can make with a APS-C that has a full frame equivalent.

Fuji A5 with 18mm F2 : 361 + 118 = 479g

This is lighter then any full frame camera and you only give up 1 stop of dynamic range at the lowest ISO.

So the question now should changed: why is a good APS-C lens heavier even though it covers a smaller sensor and image wise just equates to a 1 stop slower Full Frame. We need to look at lens construction and the demands of APS-C.

Lens components
Lens components

A lens is built up of many parts. Depending on what you use to build and how rugged you built it, more then just glass, the items around it will carry that extra weight.

If we go back and view the 24-70mm F4 by Sony, it’s made out of plastic vs the 16-55mm which is made out of metal. Considering the extra zoom and just the material difference, it is where the extra weight goes. There are probably many other things inside such as AF motor, the type of element and electronics. Many of such things do not scale in weight from Full Frame to APS-C. There’s just no way to get around physics and if you make something with a heavier material, or what to get more (range in this case) it will cost something. There are probably ways to offset such as using more exotic glass like Leica but that will bring the price to stratospheric levels.

There is also one more parameter that will result in an APS-C lens to be heavier, and that is the quality needed of the lens to perform similarly as a full frame equivalent.

Lens imperfection
Lens imperfection

Firstly, I am no lens designer and if there is a mistake I am open to corrections. That said base on my understanding, a lens job is to focus the light. Many things affect this, from the quality of the glass to the lens tolerance and design. However, no lens design is perfect. That is why sharpness varies from lens to lens and even within the same lens there is some variation. Which brings up the simplified diagram above. At the same megapixel, a Full Frame has bigger sensor sites then a APS-C. Therefore, to design a lens that can work as good on a APS-C as it would look on a full frame is actually harder as the tolerance is lower. You may be using less material due to the smaller sensor, but you will need better material and overall better quality to work as well. This usually translates to some extra weight be it more/better lens elements or material with tighter tolerance. Which pretty much explains why good APS-C lens cost quite a sum of money and probably cost more with all the glass needed for correction. A good APS-C lens can easily perform to whatever full-frame has, it just cost the same as a full-frame lens and weighs as much.

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So as you can see above, a top notch APS-C lens, the 200mm F2 by Fuji, really performs as good as anything out there and maybe a little more due to the advances in technology. Perfectly sharp, highly corrected, extreme fast AF with Linear Motor. All this can be done, at a cost that is similar to the Full Frame 200mm F2. It does come with a tele-converter and considering all the advances, it definitely is as good of a deal if not better then its equivalents.

So where does this all leave us in the end? Full-Frame and APS-C are really about the same. APS-C can be lighter by basis of smaller cameras and if you use a lens of similar built with specs comparable to its full frame counter part. APS-C performs similar to a Full Frame that has added 1 stop of ISO and using a 1 stop slower aperture lens. A Full Frame given the best condition, will always outperform a APS-C camera when it comes to image quality at the lowest ISO. Sharpness and image quality is more of a metrics of the lens then the sensor itself, unless you need the 1 extra dynamic range at the lowest ISO.

So if you want the lightest possible package, an APS-C is still the way to go. What you lose is 1 stop of dynamic range and probably 1 stop of noise compared to the best of Full Frame. That probably wont affect you as much unless you love to shoot in extremes: Extremely Dark or Extreme Bright. One needing the noise performance while other requiring the best dynamic range. Just remember that APS-C does not equate to a cheaper system or a lighter system if you want full equivalence to the full frame versions.

Of course there are still other things to consider. Very technical stuff such as read out speeds which is bias to smaller sensor size and that not all full frame performs as good as a D850 when it comes to dynamic range. If you were to browse around photons to photo, you will see modern APS-C is quite comparable to some Full Frame Sensors or almost no difference. If we are to look at the a Full Frame with similar frames per second as the XT3, that will be the A9, D5, 1DX. Non of them really performs better then the XT3 sensor in terms of image quality.

XT3, D5, 1DXm2, A9
XT3, D5, 1DXm2, A9

Comparison between XT3, D5, IDXm2 and A9

So what about Medium Format? Replace APS-C as Full Frame, Full Frame as Medium Format, and you get the same explanation. The biggest reason why Medium Format cost more and produce even higher image quality is because its a niche product, built for people who wants something better and willing to pay for it. If you get the best of everything for Full Frame, you can achieve 95-98% at maybe 80-90% of the cost. In the end, you pay for what you get and no one can beat physics for free :)

And a picture from the GFX50s, Medium Format Crop Sensor Camera

GFX50s with 110mm F2
GFX50s with 110mm F2

 

Workshops!

I’ll be holding two workshops

One is a basic studio that covers how to do simple studio photography

https://www.facebook.com/events/385071658954411/?ti=cl

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There’s also a guided workshop that focus more on shooting and I will just explain some concepts. The theme is artwork like portraits.

https://www.facebook.com/events/266998334188357/?ti=cl

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If interested do sign up at the links or email me at Richard@zpeaktures.com

Fujifilm XF 200mm F2 Preview: The Beast

XT30 with the Xf200mm F2
XT30 with the Xf200mm F2

Sometime, a maker decide to push the limit in both performance and price. A aps-c only super telephoto class prime that cost similar to those white ones you see at sporting event? This has got to be the first. Enter the Fujifilm XF 200mm F2 R LM OIS WR. The first of its class for aps-c or smaller sensor, 200mm F2 with a equivalent look as 305mm F2.8 on Full Frame. 200mm F2 are not new stuff, there’s the Canon and Nikon dating back from 1980s. Fantastic lens built with the best optics then. Both companies refreshed them in the past 10 years and when used on an aps-c, will give similar results to the one by fuji. What makes fuji special is its using the latest in optics design and built only for the smaller sensor, resulting in 10-20% reduction in weight and improved optics. At 2260g, it’s lighter then any 200mm F2 or its full frame focal length equals of 300mm f2.8.

200mm @ F2
200mm @ F2

Fuji is not one to shun from putting their latest in their more consumer centric camera. Infact their latest XT30 will out-perform the XT3 in auto focus till the new firmware is up. That may look and sound silly, mounting a small consumer priced camera that’s 1/6 the cost on a white beast of a lens. However what you get is a setup that weighs slightly over 2700g, with an F2 light gathering capability and 300mm view. There is probably no setup that performs similarly at this weight. Balance may be in issue but nothing an additional grip or monopod can’t solve, which is usually staple in such setups.

200mm @ F2
200mm @ F2

But there will be nothing great if optics are not there. And this lens delivers in spade! Extremely sharp, it even look as good as my GFX shots which is famous for sharpness. It’s also very well corrected, almost insignificant chromatic aberration (CA) at 100%. You can find some at 400% view but that’s really pushing it. The CA is also of a a light yellow variant, which is much preferred over the magenta ones.

200mm @ F2. No LOCA
200mm @ F2. No LOCA

But the biggest best thing is that minimization of longitude CA aka bokeh CA. This is a bigger issue then normal CA as they are hard to correct and tints the background especially things like silver railings above.

Speaking about bokeh, this is a cream machine. Even when compared to full frame equivalents. There’s nothing better then a 300mm f2.8 unless we take out the super teles of 400mm f2.8. And we still have f2 speed which means a faster shutter 😀

Other then optics, the lens is well built and also comes with a tele-converter. Initial test shows little drop in sharpness and with it, you can actually do some simple macro. 0.63X similar to a full frame anyone?

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And one last thing, I like the bag it comes with. Slide the lens in with the camera attached. Not bad really for a traveling solution.

So wait for my full review, where I have more close up and testing. Also look forward to more reviews especially the X, GFX and their series of equipment!

New Shoot: Embracing a new style

Recently I got hooked on to a single light with backdrop, more traditional artwork style of photos. Really nice and love the image produced.

Shot with just one large octabox above the subject. Enjoy!

Model: Karen (https://www.facebook.com/boiledcurry/)

Dress by : https://18atelier.com.sg/

Studio : https://www.lunarworks.co/

Lighting: Elinchrom Litemotiv 190, Godox AD200

Camera: Fujifilm GFX50s

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