OMD E-M1 vs Sony A-7, What's the Difference?

Started Oct 23, 2013 | Discussions thread
Anders W Forum Pro • Posts: 21,468
Re: It really depends which lens you compare with.

EarthQuake wrote:

Anders W wrote:

EarthQuake wrote:

Anders W wrote:

Raist3d wrote:

Comparing the standard zoom the difference isn't that big. Ditto for the F1.4 vs F1.8 prime.,487.393,ha,t

That the Panasonic lens here is one stop faster is irrelevant- you still get shorter DOF at will on the Sony by one stop (F4) and the sensor being bigger, you get at least 2 stops better ISO, so you can afford to have one stop less in that aperture. In fact, the Sony is still as a system faster light wise.

At least 2 stops better ISO?

A99 has light-robbing SLT. Check D600 and D800 performance if you want an idea how the A7 and A7R perform, as they are likely using the same (or better) sensors.

Perhaps not 2 stops, but 1.5 stops at least, which is quite significant.

Sure the A99 has SLT but that's not the whole story. Sony isn't Nikon when it comes to certain aspects of sensor performance, e.g., read noise, even if the basic sensor tech is sometimes the same. Go over to DxO and compare the DR curve for the entirely conventional (no SLT) A900 versus the D3X and you'll see what I mean. So it remains to be seen how Sony fares this time.

And, as you recognize, "at least 2 stops" is an exaggeration even in comparison with current Nikon FF. "At least 1.5 stops", as you claim, doesn't quite cut it either. At higher ISOs, it's more like 1.3 in terms of DR, sometimes even less.

Maybe in the past Sony couldn't get as much out of their own sensors as Nikon, the A900 is what, 5 years old now? Check the RX1 vs the D600 and D800, performance is virtually identical. Heck, even the Sony A580(last decent sony dSLR, ie: not SLT) is a match for the D7000 and K5 that shared the same sensor for everything but base ISO DR.

I can't see the A7/A7r performing any worse than the RX1.

OK. I agree on that.

Now, don't get me wrong, saying all that and assuming the A7 sensor is somewhere in the 1-2 stop better range than the EM1. The available lenses for the Sony FE mount are very limited and generally slower.

Sony 55/1.8 or Pana 25/1.4, pana is 2/3rds stop faster which comes close to negeting the sensor difference (except for narrow DOF)

Sony 35/2.8 or Oly 17/1.8 or Pana 20/1.7, m43 options are 1 1/3rd and 1 1/2 stop faster so that likely negates any real world difference.

Plus IBIS on the EM1 means shooting at much slower shutter speeds for static, or even slow moving subjects. Honestly if the A7 had IBIS (and an 85/1.8 the size of the 55/1.8 I) would seriously consider it, but without it, the EM1 will likely trounce it for real world use for most situations aside from low ISO DR/color depth.

Again, we see eye to eye on pretty much all of this.

In general, I think it's just fine that we are finally seeing some mirrorless FF cameras (aside from Leica) and I am, if anything, surprised that it took so long for anyone to get one out the door. Furthermore, as expected, the lenses for it don't really have to be larger or heavier than their MFT counterparts, if we exclude longer teles and consider lenses that can be expected to give roughly equivalent end performance rather than lenses with the same speed in terms of f-stops (which would be significantly bigger and heavier for FF).

But the way things currently stand, MFT offers a pretty capable and complete system whereas the FE mount is little more than a promise for the future. Furthermore, for my shooting needs (which rarely call for more shallow DoF than I can get with the 45/1.8 and 75/1.8 on MFT and favor "FL control" over DoF control), it would for the most part probably just break even with MFT in terms of performance for a given bulk/weight, even if Sony could deliver a complete lineup of fairly slow (in terms of f-stops) but light and small FF lenses.

So I'll be watching the scene with interest but am certainly not considering anything like a change of systems at the present stage or in the foreseeable future.

P.S. As to the difference in terms of sensor performance when we hit the low ISO border line, that's something I would expect to be effectively eliminated in the not so distant future due to the appearance of sensors with arbitrarily low ISOs using techniques like these:

This would make it possible for the MFT user to shoot at say ISO 25, f/4, and 1/100 when the FF user would have to shoot at ISO 100, f/8, and 1/100 for an equivalent image.

 Anders W's gear list:Anders W's gear list
Panasonic Lumix DMC-G1 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Panasonic Lumix G Vario 7-14mm F4 ASPH +28 more
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