[John Sadowsky Participant Posts: 169]

New Article Announcements & Discussions

on: October 19, 2019 at 8:02 pm

I am an amateur landscape photographer.  I shot with an A7R III.

Which is more cost effective?  Buy a long lens for my full frame camera, or buy crop sensor body (a micro 4/3) with a long lens for that format?  I understand that “light gathering” is determined by lens diameter regardless of sensor size, or focal length.  So down sizing on the sensor doesn’t mean downsizing on the physical size, or cost, of the lens.  What do you recommend?

JSS

[Brad Smith Participant Posts: 31]

Re: Micro 4/3

Reply #1 on: October 21, 2019 at 3:13 pm

John, you didn’t say what focal length range you’re looking at for your Sony and whether you want zooms or primes.  In any case, in my opinion, big, f2.8 and f4  heavy long zooms and primes are good for a landscape photographer ONLY if you shoot in very dim light or want absolute narrowest depth of field images.  The cost, length and weight are just not worth it unless you’re  young, strong and very well to do.  I went from a Canon APS-c system with a 70-200 f4 L as my longest lens to an Olympus micro 4/3 with a 40-150 at a much smaller weight and size.  And I’m perfectly satisfied with my quality in prints up to 17×25.  Here is a comparison of the top of the line alternatives…….popular full frame Sony 70-200 f2.8 $3,000 and the equivalent micro 4/3 Pany 35-100 f2.8  $900,   And for primes, the 600 f4 Sony $13,000 with the Olympus 300 f4 $2500.

[John Sadowsky Participant Posts: 169]

Re: Micro 4/3

Reply #2 on: October 21, 2019 at 3:45 pm

I should have been more precise.  I’m interested in doing some widelife photography, which is what I wanted a long lens for.  I would like to have something in the 300-600 mm range for FF.  All else equal, is it more cost effective at micro 4/3?

I differ with you on equivalence comparison.  When comparing across different sensor sizes, it is equal lens diameter, not f-number, that results in the same focus and exposure properties.  For the same exposure time and DoF (or hyperfocal distance), shooting at f2.8 in FF is equivalent to f1.4 for micro 4/3.  So that 70-200 comparison both at f2.8, of course the micro 4/3 lens is cheaper, but it is a much smaller lens and not as fast.

A better way to express the question is as follows.  For equivalent lenses, where equivalence means equal diameter and a focal lengths scaled by the crop factor, do micro 4/3 lenses a cost advantage?  I might have to go to B&H and start doing that comparison – enquiring minds want to know.

JSS

[John Sadowsky]

Re: Micro 4/3

Reply #3 on: October 21, 2019 at 5:58 pm

OK, I did some lens comparison using B&H pricing.  I searched for mirrorless only, in the telephoto categories – primes only.  The problem is that there isn’t a very big selection.  In order to compare prices of lenses with different focal lengths, for each lens I calculated it diameter = f/N, and then the area.  My hunch is that lens area would be the most significant cost determining factor.

There were only a few lenses in the FF category.  The top end are

Sony GM 400 mm f2.8 at $0.59/mm2
Sony GM 600 mm f4, at $0.58/mm2

(mm2 = square mm – can’t do a superscript here.)  Both these lenses have about the same diameter (143 and 150 mm respectively).

There where several 135mm FF lenses

Rokinon f2 at $0.11/mm2
Sigma f1.8 at $0.29/mm2
Sony GM f1.8 at $0.37/mm2
Zeiss Batis f2.8 at $0.51/mm2

For micron 4/3, the longest lenses were

Olympus 300 mm f4 at $0.57/mm2
Panasonic 200 mm f2.8 at $075/mm2

The Olympus 300 mm is price comparable to the Sony GM 400 and 600 in the FF format; that is, in terms of price per lens area.  However, the diameter of that lens is only 75mm, compared to the Sony GMs having a ~150 mm diameter.  That’s the difference between $12,000 lens (the Sony FFs) and a $2,500 lens (the Olympus 300 mm).  The Sonys are faster lenses.

The Panasonic seems to be  a price outlier.

At shorter focal lengths Rokinon 135 mm f2 was the cheapest at $0.13/mm2, while the Olympus 75 mm f1.8 is the high end as $0.66/mm2.  Other lenses landed in the $0.30-$0.50/mm2 range.

Conclusions

The sample size of this experiment is small, but I think the data supports my price-to-lens area ratio approach.   We expect Sony GM, Zeiss and Olympus to be expensive, because those are higher quality brands.

The Olympus – Sony comparison seems to show that micro 4/3 does not have an inherent lens cost advantage over FF.  The Olympus lens is a lot less expensive, but it is also a much slower lens.

JSS

• This reply was modified 4 years, 9 months ago by John Sadowsky.

[Kevin Raber Silver Member Posts: 1311]

Re: Micro 4/3

Reply #4 on: October 21, 2019 at 9:12 pm

I still believe folks buy these cameras for different reasons.  Olympus is very popular with serious photographers that take lots of trips or want something light for hiking etc.  If you aren’t worried about big prints the Olympus is a feature-heavy well-built camera system.

Kevin Raber
Owner and Publisher of photoPXL

[Brad Smith Participant Posts: 31]

Re: Micro 4/3

Reply #5 on: October 21, 2019 at 9:15 pm

John, you said….

John Sadowsky wrote:

When comparing across different sensor sizes, it is equal lens diameter, not f-number, that results in the same focus and exposure properties.

I’m afraid that only part of your statement is correct.  I think everyone would agree with you about them not being equivalent for depth of field, but they are exactly equivalent for exposure.  If a scene needs 1/1000 at f8 in the Sony 600mm, it will also need 1/1000 at f8 in the Oly 300mm.  Yes the 2.8 Sony lets in more light, but it must cover a larger sensor than the Oly, and therefore, each pixel site receives the same amount of light in each lens.

So if lenses are what we are considering (rather than # of pixels or dynamic range or other camera features), the choice comes down to a comparison on a lens to lens basis of cost, size and  weight.  All of these lenses have been very well reviewed and I don’t believe that lens resolution is a differentiator.

I must confess however, that, as a retired engineer, I admired your creation of a new photography metric for lenses…..$/sq mm.  I don’t think it has anything to do with this discussion for the reasons I’ve stated, but it brought a smile to my face.

Here’s a solution for you…..rent a big, long, heavy prime for your Sony and simultaneously rent a micro 4/3 body and the Oly 300.  Shoot with both and carefully look at the files at printing size.  There is a lot of money at stake in your decision, so this would, I think, be money well spent.

Brad

Brad

[John Sadowsky Participant Posts: 169]

Re: Micro 4/3

Reply #6 on: October 21, 2019 at 10:34 pm

No sir.  Same shutter speed and aperture on different sized sensors are not equivalent exposures.  An equivalent exposure should deliver the same total amount of light to the sensor; that is, the same number of photons.  It is the sensor’s job to convert that light to a digital image.  It is a simple fact of geometry that the light gathering capability of the camera is determined by lens diameter – not f-number.  So when you say the same shutter speed and same f-number is an equivalent exposure for two different sensor sizes, what you are actually saying is that the smaller sensor deserves fewer photons.  Modern digital photography is largely limited by photon noise.  Fewer photons is not an equivalent exposure.

You have to compose the equivalence question as follows:  what does it take to take to capture the same image, with the same focus properties and the same image noise across the image.

Go to Wikipedia and look up the formulas for hyperfocal distance and DoF.  They are functions of N and c = the circle of confusion.  You have to scale c by the crop factor, because images should be compared on the bases of the same circle of confusion relative to the sensor size.  Eliminate N using N = f/D where D is diameter.   What you will find is that to get the same hyperfocal distance, and the same DoF, requires equal diameter lenses.  With equal diameter, equal exposure time then yields that both sensors are provided the same number of photons.

I’ve not talked about resolution.  For equal sized photosites (which is more or less constrained by semiconductor physics), the larger sensor has better resolution.  But we can’t compare images unless we agree to have the same circle-of-confusion relative to sensor dimensions.  The larger sensor have more Mpix, which only means they can take higher resolution images than the crop sensor.  But to compare we have to set a common resolution (circle-of-confusion relative to sensor dimension) that both cameras can shoot.  That can be done by resizing to, say, 8 Mpix (the “print” standard) then comparing on the basis of equal SNR.  That exactly what equal diameter and equal exposure times does.

I didn’t invent this.  It is a common misconception that smaller sensors make everything smaller and cheaper.  But when it comes to lenses – its just not true.  Equal diameter lenses are roughly the same size and weight regardless of the sensor size, and the limited data I looked at indicates that they are of comparable cost.  There may be other factors that make one format more cost effective than another.  (For one thing, if you want to realize the larger potential resolution of the larger sensor, you have to have a lens that can meet that resolution.)  That’s why I originally asked the question about cost comparison.  However, the bottom line is that the advantage of larger sensors is that they are capable of taking higher resolution images than crop sensors.

JSS

[John Sadowsky Participant Posts: 169]

Re: Micro 4/3

Reply #7 on: October 22, 2019 at 10:07 am

Kevin Raber wrote:

I still believe folks buy these cameras for different reasons. Olympus is very popular with serious photographers that take lots of trips or want something light for hiking etc. If you aren’t worried about big prints the Olympus is a feature-heavy well-built camera system.

Absolutely!  I’m not discounting the value of smaller formats.  They certainly have their niche.  I hope I are not coming across as being belligerent – that’s not my intent.

Equivalence theory (comparing across different formats at equivalent image quality) turns out to be a more complex topic than many people think.  For those looking for some serious torture, here is a link to a technical article on it:

https://www.spiedigitallibrary.org/journals/optical-engineering/volume-57/issue-11/110801/Equivalence-theory-for-cross-format-photographic-image-quality-comparisons/10.1117/1.OE.57.11.110801.full?SSO=1

 

JSS

[John Sadowsky]

Re: Micro 4/3

Reply #8 on: October 22, 2019 at 10:19 am

Brad Smith wrote:

Here’s a solution for you…..rent a big, long, heavy prime for your Sony and simultaneously rent a micro 4/3 body and the Oly 300. Shoot with both and carefully look at the files at printing size.  There is a lot of money at stake in your decision, so this would, I think, be money well spent.

Great advice!  I will definitely rent before spending $12,000.  Still, for wildlife photography I am concerned about lens speed.  I had a Nikon 70-300 mm on my D700, but at 300 mm its was f5.6.  It was great for parties with a powerful shoe flash, but I found it to be too slow for outdoor shooting at 300 mm  except in the brightest daylight, and not really long enough for a lot of wildlife.  No doubt about it – wildlife is an expensive hobby.

JSS

• This reply was modified 4 years, 9 months ago by John Sadowsky.

[Author]

Posts