Micro Four Thirds - do we kid ourselves somewhat?


Chris_L 5 5.1k United Kingdom
2 Mar 2016 7:04PM
With the arrival of the Panasonic 100-400mm f/4-6.3 comes some very positive reviews and some nice sample images.

Inevitably reviewers can't resist saying that it's like having a 200-800mm lens on a large dslr; and that somehow makes the 1,300 price tag more palatable.

I fell in love with MFT but I'm starting to think that some aspects are talked up a bit and comparisons like the above don't tell the whole story, it's not an accurate picture. I might be wrong, I sometimes make basic mistakes with arithmetic.

Compared to my previous camera, 5D, my GX7 and GH4 have sensors that are half the size. Correct me if I've got that wrong.

Is buying a GX8 with 12-35 lens really equivalent to buying a A7R-II with a 24-70 lens - aren't the images from the GX8 actually just like crops from the latter camera?

Where DOF is concerned isn't f4.0 on MFT more equivalent to f8.0 on full frame?

Or, put another way. does 1300 quid spent on the Panasonic 100-400mm f/4-6.3 really get you the same images that you'd get from an 800mm lens on a full frame camera? Is it a somewhat misleading comparison?

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Paul Morgan 18 19.3k 6 England
2 Mar 2016 7:57PM
It all depends on what bits bother you, if all your interested in is dof comparisons then its probably not.

I had the Olympus 35-100 f2, some people thought of this lens as being silly expensive, I found that it was really pretty cheap considering what I was getting, no other lens manufacture built a 70-200mm f2 and this was basically what I was getting.

What would you rather spend you money on Chris, a 10K Canon 600mm f4 or a 2k Olympus 300mm f4 (personally neither would interest me I don`t use long lenses) but both will deliver similar results.

I think people worry them selves far too much with crop factors, especially at the 35mm or smaller level and 35mm is still small compared to other formats.
srh 15 54 1 United Kingdom
2 Mar 2016 8:39PM
I'm under no illusions. You get the same FOV in the comparisons you make, but not the same IQ. However, my GX8 and m4/3 lenses gives me IQ which is way more than 'good enough' for pretty much every shooting situation I find myself in.

Simon.
Chris_L 5 5.1k United Kingdom
2 Mar 2016 10:06PM

Quote:What would you rather spend you money on Chris, a 10K Canon 600mm f4 or a 2k Olympus 300mm f4

This is the whole problem, the suggestion that the two are equal. I don't think they are equivalent.
Paul Morgan 18 19.3k 6 England
2 Mar 2016 10:53PM
I guess it all depends on what bits bother you, me or anyone else, the parts that generally bother me are equal or equivalent (most of the time)
Carabosse 16 41.2k 270 England
3 Mar 2016 2:28AM
Let's face it whether MFT, or any larger format, digital photography gives us quality which 10-12 years ago we could only dream of!

Back then, 6Mp on a 1.6 'crop' sensor was pretty much state of the art. And people on here would say "Why on earth would you ever need anything more?" wink-light.jpg



As to DoF, many would welcome the increased DoF you get by using a specific aperture on MFT as compared with FF on lenses with the same angle of view.
Lenscapon 3 64
3 Mar 2016 6:03AM
I recently moved from MFT (Lumix G2 and then a GX7 with a selection of Olympus and Leica lenses) to an APS-C crop sensor Fuji X-E2 with a selection of Fujinon lenses.

I agree that the MFT system has some great lenses (I think the Olympus 45mm is a modern classic) and for most uses the IQ is good enough. And the long lenses you are looking at are smaller and lighter than the equivalent for larger sensor systems. But ...... low light capability is still behind that of bigger sensors and the sensor size will obviously have a direct impact on DOF.

I moved to a larger sensor as I'm interested in portraits, so the narrower DOF is an advantage to me. But if I'm doing macro or landscape I still use the GX7.

So predictably it depends on your main interests, but for me I wanted to make the change before I invested any more in MFT lenses, and after buying that big zoom lens you'll be locked in to MFT!
brian1208 Plus
16 11.5k 12 United Kingdom
3 Mar 2016 7:17AM

Quote:Or, put another way. does 1300 quid spent on the Panasonic 100-400mm f/4-6.3 really get you the same images that you'd get from an 800mm lens on a full frame camera? Is it a somewhat misleading comparison


My thoughts are that, regardless of price I will take an EM-1 with a 100 - 400 lens attached (in my case its more likely to be the canon EF100-400 though Smile ) with me in my sling bag but there is no way I could dream of doing the same with an 800mm lens


Quote:So predictably it depends on your main interests, but for me I wanted to make the change before I invested any more in MFT lenses, and after buying that big zoom lens you'll be locked in to MFT!

rings true for me too, it is one reason (price being the other) I'm using the EF 70-300 LIS on the EM-1 at the moment and am considering the EF100-400 as I'm about to add a canon 7D mk2 to my kit and I can use those lenses on both bodies
3 Mar 2016 10:12AM
First about numbers. It is the size of diagonal that is 1/2 size of diagonal of full frame camera. Which means that sensor area is actually 1/4 of full frame. However, this is sort of irrelevant to equivalent focal lenghts. They are calculated by crop factor, i.e diagonal dimensioms.
So yes, 400 mm with m4/3 will produce the picture with the same angular size of diagonal as 800mm with full frame at the same distance from the subject.
And here the similarity ends - as it will be different or radically different picture given to circumstances.
First, and obvious, you are correct. F4 , 400mm will give sort of the same dof with m4/3 as f8, 800mm with full frame.
But this "sort of" comes with slightly different close and far limits that at distances of about 100 feet may be as much as a foot or two. And this may be a great deal composition wise.
Then, at a particularly sunny day there will be a trouble using high ISO to freese the movement. Anyway, even with electronic shutter ISO and shutter speed combination will be different to full frame. Any experienced photographer will know what it means.
Then, at this range of focal lenghts atmospheric imperfections are not negligible. And they would not scale in relation to sensor size and focal length, here comes to play absolute, not relative aperture, i.e.absolute (physical) diameter of the lens.
So, you are correct here - justifying lens price by the assumption that it will produce the same result as longer focus lens in full frame is no more than marketing trick The result may be even better -given right set of circumstances, but under other set of conditions it may be noticeably worse, if not unusable. So it sure will be different most of times. And every time if we compare to APS -C for very simple reason that the frame ratio is substantially different.
Philh04 Plus
13 2.0k United Kingdom
3 Mar 2016 10:56AM
I am not going to type reams and reams on the subject of equivalence... if it is OK here is a comprehensive article on the subject, take heed it is a hefty read mind, so best saved for when you have some downtime....

https://photographylife.com/sensor-crop-factors-and-equivalence

If it is not OK then please delete.

Phil
Chris_L 5 5.1k United Kingdom
3 Mar 2016 2:03PM
Appreciate that Phil, I think Michael nails it pretty much, it's how I suspected it is and the blurb that says "equal to XX on a 35mm frame" fails to tell the whole story. I like all of the size and weight advantages of MFT kit.
Philh04 Plus
13 2.0k United Kingdom
3 Mar 2016 2:36PM
Your welcome... I think it is important to remember that DoF will be identical at the same aperture if you shoot with the same lens on a smaller sensor and on a larger sensor with both cameras exactly the same distance from the subject, but that is mainly for myself as I shoot 'Full Frame', APS-H and APS-C.

Perhaps more important is should we really be concerning ourselves with the intricacies of equivalence, its horses for courses and how we use our chosen equipment that is important, these days when asked these types of question, I tell people not to worry and go out and just shoot images and enjoy.

Best

Phil
brian1208 Plus
16 11.5k 12 United Kingdom
3 Mar 2016 2:43PM
Nicely put Phil, I used to worry about the science behind these questions but now all I care about is "does it help me do what I want?" Smile
Carabosse 16 41.2k 270 England
3 Mar 2016 2:52PM
Yes, it's important to use the right equipment for the specific task - otherwise things can become a bit unbalanced! Oops! tongue-light.jpg



9207_1457016720.jpg



ChrisV Plus
12 2.3k 26 United Kingdom
3 Mar 2016 3:15PM
It may sound hubristic, but I don't think I've ever fooled myself with regards to what I'm getting with MFT. The 2x crop factor as Michael says is because the scaling is diagonal meaning you could actually fit four MFT sensors into the area of one 35mm format. That means you're getting four times less light at the same f stop, which, following the inverse square rule, means 2 stops less. That's two stops in terms of limiting DoF and all things being equal, two stops in terms of image noise.

But aside from the limitations of diffraction and subtle changes in focal length [in truth you can get those even using different lenses from different manufacturers nominally marked as equivalent for the same lens mount], these things only make a huge difference once you get to the edges of capability in any given situation.

To give an example, a job I was doing yesterday was at a kids event in a woefully lit town hall. I had my EM1, GX8 and a variety of lenses. Most of the shots I wanted were the 'casual action' from a distance shots to get candid, unposed shots. I had the 35-100 f2.8 on the GX8 and the old 50-200 f2.8-3.5 SWD FT lens. The latter whilst quite big and not really quick focus, is a sharp lens and reasonably fast [in the terms we're talking about] and it benefits from the superb IBIS of the EM1. The problem was, the light being so bad that even wide open the auto ISO was at or beyond the limit of acceptability and although the slow shutter speeds were still delivering sharp shots, they were also delivering sometimes image ruining motion blur [of subject].

The upside of this is that limitation of DoF at these sort of focal lengths/apertures is not much of an issue - you're going to get sharp fall-off of focus in any case even if you are talking of the equivalent of f5.6 vs f2.8 - there are also no issues with focus misalignment you get from a separate PDAF sensor. What was an issue was the bad light and image noise. BUT [that's a big but], if I were shooting 35 format at 400mm, I'd have a bigger lens I might have to tripod mount and most likely no IS unless that lens was a very expensive one. So there are swings and roundabouts.

At the intermission, I got the organisers to open [some] of the curtains and all of a sudden I had a good four stops plus of extra light, giving me higher ISOs and faster shutter speeds [meaning far more detailed, smoother images with no subject blur usually].

I'm not sure I've ever actually been in a situation where the light was quite that challenging. But it turns out some of the curtains being open was not a big issue and that extra four [and counting] times light, cost me nothing.

There are lots of swings and roundabouts to formats and lenses - the important thing is to make a choice from a position of knowledge. Personally [because I rarely need fast and accurate tracking] I miss 35mm format more at shorter focal lengths than long ones, because f2.8 at 12mm [the wide end of the standard zoom on MFT] is next to useless for subject isolation. There are some good primes to take up the slack, but it's still a limitation you need to bear in mind. As with anything though, it all depends on what type of image you want to capture and in what environment.

Whatever you choose there's always a price to pay....

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