The DOF "Advantage" from a smaller-sensor camera?

The other day I stumbled upon a blog by a pro photog where she was advocating the benefits of Micro 4/3 sensors and how full-frame is not always superior. I wish I could find it again, but I didn't bookmark it. But I have heard this line of thinking before elsewhere.

Basically that you don't always want shallow DOF, for example if you are shooting a low-light event and want say a group of people in focus, more DOF can be an advantage. Therefore a smaller sensor camera allows the light-gathering ability of shooting at a wider aperture combined with larger DOF.

It somewhat makes sense to me, but otoh, doesn't the larger sensor's higher capability in low-light offset that? I've generally noticed at least a 1-stop advantage in low-light from my 6D than ANY APS-C sensor camera I've used so far. So if I need more DOF, I can just stop down 1 stop, and then bump up my ISO, and my pictures still look as "clean" with similar DOF as shooting the APS-C sensor camera.

Not trying to start a full-frame vs others thing, by golly we have enough of that already. I definitely think cameras of all sensor sizes have their place, as apparent in my gear list . I'm just wondering if the above argument, that smaller-sensor cameras give you the "advantage" of more DOF, is really valid.

http://lindsaydobsonph​otography.com …rame-v-micro-four-thirds/

Here?

You can also back up to get more DOF, it's not always related to aperture.
Focal length also plays a vital role.

The Dark Knight wrote in post #16728968
I'm just wondering if the above argument, that smaller-sensor cameras give you the "advantage" of more DOF, is really valid.

Yes, I find it very valid. I agree that in low light my 5D III could stop down much more than my fuji bridge camera, by using a higher ISO and that would counteract the advantage though.

For me, I use a smaller sensor bridge camera for shooting my ebay product shots. I sell wargames figures and they are pretty small so I need to get in close to show the detail, and I often need quite a deep DOF, if I have several in a lot and they are arranged in a loose group for some shots. Even stopping down the lens on my 5DIII to really small apertures doesn't give me the same DOF as I can get from the fuji, even though the fuji won't stop down past f/8 (due to risk of diffraction issues, I presume).

maverick75 wrote in post #16729291
You can also back up to get more DOF, it's not always related to aperture.
Focal length also plays a vital role.

These points are correct, but are not very good ways of controlling DOF. If you back up more you do get deeper DOF, but you also need to use a longer focal length to maintain the framing, which reduces DOF again by about the same amount. Of course, you can keep the same FL and crop in post, but that also reduces the DOF again, due to the extra enlargement.

Any image that you can take with a micro-4/3 camera, you should be able to take an equivalent image using a full-frame. For example, an image shot a f/2.8, 1/100s, ISO 100 on m-4/3 will be equivalent in every way to that taken on a full-frame at f/5.6, 1/100s, ISO 400 (also assuming here that the lens focal length is doubled on the FF, to give the same angle of view).

The problem is that it doesn't quite work both ways. It will be very difficult to produce an equivalent image using m-4/3 for a FF image shot at f/1.4. But this may not be important to some.

m4/3 has its advantages and FF (or APSC) have their advantages. They all have their disadvantages. Get what works for you and shoot

The advantage of larger DOF with m4/3 can be good, for example, in the studio or outdoors. I can shoot f1.8 and still have the entire face in focus but still get 1.8 light to my sensor. Landscape type shots I have a larger DOF as smaller apertures so that can be an advantage.
I focus more on the size and weight benefits when looking at smaller sensors...I'm getting pretty sick of big weight and size for my personal use.

John from PA wrote in post #16729265
http://lindsaydobsonph​otography.com …rame-v-micro-four-thirds/

Here?

Yes, that's exactly the article I stumbled upon

Steve-R wrote in post #16729330
Any image that you can take with a micro-4/3 camera, you should be able to take an equivalent image using a full-frame. For example, an image shot a f/2.8, 1/100s, ISO 100 on m-4/3 will be equivalent in every way to that taken on a full-frame at f/5.6, 1/100s, ISO 400 (also assuming here that the lens focal length is doubled on the FF, to give the same angle of view).

The problem is that it doesn't quite work both ways. It will be very difficult to produce an equivalent image using m-4/3 for a FF image shot at f/1.4. But this may not be important to some.

This was kind of what I was getting at. You can get the same "DOF" by stopping down on full-frame, and the higher ISO ability should compensate for less light entering the lens, no?

For a specific format, DOF is ultimately tied to the reproduction size of the object on print. But with different format size, one needs to use aperture appropriately larger (with same size relationship to FL of lens used).

1. 4x5" (95x120mm frame) film with 190mm lens focused at 48" using f/16, frames 22" x 27" with DOF 46"-50"
   
2. 35mm (24x36 mm frame) with 50mm lens focused at 48" using f/16, frames 22" x 33" with DOF 40"-59"
   
3. APS-C (15x22.5mm frame) with 32mm lens focused at 48" using f/16, frames 22" x 33" with DOF 37-67"
   

• 4x5" (95x120mm frame) film with 190mm lens focused at 48" using f/16, frames 22" x 27" with DOF 46"-50"
• 35mm (24x36 mm frame) with 50mm lens focused at 48" using f/5.6, frames 22" x 33" with DOF 45"-51"
  
• APS-C (15x22.5mm frame) with 32mm lens focused at 48" using f/3.5, frames 22" x 33" with DOF 45-51"

To frame the same shot, at the same aperture, from the same distance will require a much shorter lens with full frame. If you are after DEEP DOF, FF is the way to go. At the same aperture and focal distance, the shorted lens REQUIRED for full frame will ALWAYS give you MORE DOF than the longer lens on subframe. No advantage at all. What you would see in practice in a hindrance to DEEP DOF with subframe. Your theory is exactly backwards.

I own and shoot both formats. The difference, in real shooting, is non-existent. Play with this if you don't have both formats:
http://www.dofmaster.c​om/dofjs.html

GaryD wrote in post #16729863
To frame the same shot, at the same aperture, from the same distance will require a much shorter lens with full frame. If you are after DEEP DOF, FF is the way to go. At the same aperture and focal distance, the shorted lens REQUIRED for full frame will ALWAYS give you MORE DOF than the longer lens on subframe. No advantage at all. What you would see in practice in a hindrance to DEEP DOF with subframe. Your theory is exactly backwards.

I own and shoot both formats. The difference, in real shooting, is non-existent. Play with this if you don't have both formats:
http://www.dofmaster.c​om/dofjs.html

I believe that you have it backwards. For a given shot with constant framing at the same aperture, a full frame sensor will REQUIRE 1.6 times the focal length that the crop sensor requires. So a crop would REQUIRE 50mm while the full frame would REQUIRE 80mm, giving the crop sensor a deeper depth of field at a constant aperture.

lol another Ken Rockwell wannabe
If what she says is true then the m43 format should be very popular with landscape photographers

CallumRD1 wrote in post #16729881
I believe that you have it backwards. For a given shot with constant framing at the same aperture, a full frame sensor will REQUIRE 1.6 times the focal length that the crop sensor requires. So a crop would REQUIRE 50mm while the full frame would REQUIRE 80mm, giving the crop sensor a deeper depth of field at a constant aperture.

I have no idea what I was thinking (or IF I was thinking) when I wrote that. I will leave the original post intact so everyone can see what a real brain-fart looks like. Of course, the quoted post is completely insane. I blame the Dundee Pilsner for that.

FuturamaJSP wrote in post #16729924
lol another Ken Rockwell wannabe

I suspect this remark was intended as an insult. However I should point out that Mr Rockwell is a Canikon fan who expends very little time or energy giving credence to alternative systems, quite often "reviewing" equipment he has never held let alone used. He is also in the habit of inviting donations, whereas my blog is a free resource to anyone who wishes to read it.

If you had looked at my website, you would see that I'm a full-time working portrait photographer who comments about the equipment relevant to my work. Quite simply, if I'm using that equipment in order to make my living then I'm well placed to comment about it, and to compare it with other equipment which I also own. I also stress, repeatedly, that my opinions are just that - my views, based upon the work I do and the way in which I carry out that work, and each reader may have different needs and preferences. No one has to read my articles, you're free to bypass everything I say in favour of your preferred sources. But I don't think the comparison with Ken Rockwell is a particularly clever one, or helpful to whatever point you wish to make.

The Dark Knight wrote in post #16728968
The other day I stumbled upon a blog by a pro photog where she was advocating the benefits of Micro 4/3 sensors and how full-frame is not always superior. I wish I could find it again, but I didn't bookmark it. But I have heard this line of thinking before elsewhere.

Basically that you don't always want shallow DOF, for example if you are shooting a low-light event and want say a group of people in focus, more DOF can be an advantage. Therefore a smaller sensor camera allows the light-gathering ability of shooting at a wider aperture combined with larger DOF.

It somewhat makes sense to me, but otoh, doesn't the larger sensor's higher capability in low-light offset that? I've generally noticed at least a 1-stop advantage in low-light from my 6D than ANY APS-C sensor camera I've used so far. So if I need more DOF, I can just stop down 1 stop, and then bump up my ISO, and my pictures still look as "clean" with similar DOF as shooting the APS-C sensor camera.

Not trying to start a full-frame vs others thing, by golly we have enough of that already. I definitely think cameras of all sensor sizes have their place, as apparent in my gear list . I'm just wondering if the above argument, that smaller-sensor cameras give you the "advantage" of more DOF, is really valid.

I mostly shoot with a wide depth of field. Subject isolation can be overdone in my opinion if every photo one after the other is the same thing. People are always talking about "tack sharp iq" and then isolate one single part of the frame by using wide aperture all the time. In certain circumstances it's great, but like every other technique is overcooked all too often.