This one is familiar to many smaller format users and I know before I start what the outcome will be, but for your and my benefit, here is the thought process. This post should really be titled “Being a Content M43 User part 2”, but I am not going to put that much thought into it.
I am contracted to a school.
Their standards are high and their catalogue of previous work is deep.
I know from my previous work that I can match what I have seen, but the nagging little voice in the back of my brain pan keeps saying “do you think you will need full frame?”.
Image Size.
I already have a large image sample, taken with an old OMD and a slightly better than kit lens (75-300), using “snap shot” technique (at best), that has been enlarged to a 3x4 foot wide sign, after some cropping. That is the size reality addressed. I know that 16-20mp is enough to max out most printing formats, especially if logical viewing distances are factored in. Full frame would increase the maximum possible enlarge-ability of the file, but not by much and should not be necessary. The reality is, photographers have been doing billboards with less for years.
Light gathering and image noise.
This one is tricky. From a purely technical perspective, there is little need for a larger format all things being equal.
Firstly there is the critical mass of the math. If an image needs to be taken, the light available will be (in non artistic or astronomical fields), good enough to see by, so good enough to photograph within a reality envelope I can reach.
Then there is the image making format math. The depth of field to reach to light gathering balance M43 gives me is usually a good balancing point for full frame.
Let me explain.
First the foundation to the argument;
F1.8 in M43 has about the same depth of field as F2.8 in full frame at the same effective magnification.
If we accept that 2.8 is the pro’s “working” and often widest available aperture, using a full frame standard or workhorse tele zoom, as it offers good low light performance and enough realistic depth of field to be in the comfort zone of soft backgrounds and sharp subjects, then M43 matches it with cheap, light primes at F1.8 at two ISO settings lower. Sure, the full frame user can pop on a 135 f1.8, but at what cost and bulk and then you still have the issue of very shallow depth of field that is often not practical (it is more practical at longer distances, but the magnification falls away, forcing cropping…). I have owned a Canon 135 f2 and very rarely used it at f2, but my 75mm f1.8 (150mm f2.8 equiv.) is used at f1.8 regularly.
Shot wide open at f1.8 on my 75mm. Any longer (an actual 150mm) or with a wider aperture and the focal point would be pretty twitchy. Thinner depth of field is often only useful for exaggerated Bokeh effect, not practical subject coverage.
This is the important bit. At the above outlined safe maximum working aperture, an M43 camera can use ISO 800 when a full frame is using ISO 3200. Have a look at the noise in the EM1 mk2 RAW file at ISO 800 compared to the Z6 Nikon at ISO 3200 on DPreview. They are nearly identical. The difference is even less if you look at the “print” image sample.
The reality is, for most critical work I will need some lighting control, not high ISO performance. The times this will not be the case are performance images (already done) and winter sport photography, that will never have unrealistic quality or big enlargement needs.
Glass.
Then we come to the lens issue, which is where M43 started for me.
Note; M43 lenses have a 2x cropping factor.
To get the best full frame glass from Nikon, Sony and Canon costs big dollars for big glass and unfortunately, many of the affordable Canon and Nikon offerings are still designed for SLR’s, making the thought of spending big bucks on them even less enticing. Even if I did go that way (within budget), the cropping needed to match the M43 lenses I have (600mm equiv) would take much of the full frame quality edge away. (Canon is releasing an affordable 100-500 zoom soon and some new cameras, but how much and how soon?)
The powerful end of the M43 lens range is very approachable. I switched to M43 when I realised that my favourite Canon glass* was matched or bettered by their tiny equivalents in M43.
The future of Olympus aside, I have plenty of good options at hand now (35-150 equiv at F1.8) and available, covering the core of the professional’s pro zoom range.
This process is irrelevant and tiring, but when your livelihood and reputation are at stake, all options need to be looked at. The reality is, bigger format potentially create better quality, but quality needed and potential quality are often not the same. Cropping to make up for focal length shortages, using smaller apertures and higher ISO settings than desirable for depth of field reasons and choosing not to buy or carry every option due to price or weight are all valid points of consideration, not excuses.
*35L = 20 Pana, 135L = 75mm Oly, 400L f5.6 = 75-300 Oly and 85 f1.8 = 45m Oly.