# Sensor or lens advantage ?



## enerlevel

Hi all,
 I have been using full frame for pretty much most of my photography life. Just recently I switched to Sony a7x series for light weight and sensor advantage. However I was mostly limited to 28mm f2. 
Looking at most of my shots, I need less DOF as I am mostly shooting groups. I mostly shoot at around f6-7..
Now I have been thinking about switching to apsc with a fast lens.. something like xt20 with 23mm f1.4 or 35mm f1.4. This will give me two advantages
1) I have few extra stops of light compared to  (28mm f2) which means with my a7x and 28mm f2 combo,  I am using iso12800.. then with the fuji and 23mm f1.4 I would be using iso 6400?

2) because of the sensor size, I would actually be using f4 rather than f6-7 on full frame to get my group shots thus again using lower iso and lower noise... 

What do you guys think about this? Can a faster lens or lower aperture compensate for a full frame sensor in my case? 
Thanks


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## Derrel

I am not sure what you mean about needing "less depth of field" since you are mostly shooting groups.

The depth of field difference between FX sensor size and APS-C sensor size is somewhat noticeable at certain distances and at certain picture field of view distances; the differeces can add up. APS-C often pulklks the background into clearer focus than does FX, due to lens length choices that often arise with a group shot; often the APS-C shooter will be forced into using a short focal length lens, to make up for the "Crop Effect", and when he uses a 30 to 35mm lens length to GET a group of people into a picture framed up from 15,20,25 feet, the background on an APS-C shot comes into clear, recognizable focus to a higher degree than with FX.

You are discussing what has become known as "equivalence", but your comment about needing "less depth of field" for group shots is perplexing. ALSO, using a 28mm lens at IS 12,800 for group photos? That means you're shooting grouop shots under abysmally dim lighting. THis sounds like the type of situation where a new camer or a new lens is the last thing needed, and the first thing needed is ancillary lighting.


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## Gary A.

I don't get a lot of this ... I understand the specs ... but Like Derrel, I don't understand the need and/or why.  A full frame will deliver less noise at similar ISO than a APS-C.


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## enerlevel

Hi thanks for the reply,
Sorry for my confusing statement, I might have said it wrong...
So basically for what I have noticed is that when shooting with similar focal lengths on apsc and full frame for example 23mm in apsc and 35mm on full frame, I can use a lower F stop to attain similar focus results..
As an example, if I chose to shoot with the 28mm FF @f6 to get all my group shots in focus, then I might use f4 on apsc to get similar results. And because of this, I be using lower iso on apsc. Yes flash is option but sometimes it's hard to travel with a flash or use it in some places.



Derrel said:


> I am not sure what you mean about needing "less depth of field" since you are mostly shooting groups.
> 
> The depth of field difference between FX sensor size and APS-C sensor size is somewhat noticeable at certain distances and at certain picture field of view distances; the differeces can add up. APS-C often pulklks the background into clearer focus than does FX, due to lens length choices that often arise with a group shot; often the APS-C shooter will be forced into using a short focal length lens, to make up for the "Crop Effect", and when he uses a 30 to 35mm lens length to GET a group of people into a picture framed up from 15,20,25 feet, the background on an APS-C shot comes into clear, recognizable focus to a higher degree than with FX.
> 
> You are discussing what has become known as "equivalence", but your comment about needing "less depth of field" for group shots is perplexing. ALSO, using a 28mm lens at IS 12,800 for group photos? That means you're shooting grouop shots under abysmally dim lighting. THis sounds like the type of situation where a new camer or a new lens is the last thing needed, and the first thing needed is ancillary lighting.


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## BananaRepublic

Do you carry a tripod?


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## Ysarex

enerlevel said:


> As an example, if I chose to shoot with the 28mm FF @f6 to get all my group shots in focus, then I might use f4 on apsc to get similar results. And because of this, I be using lower iso on apsc.



You will not gain a noticeable advantage in noise from the APS camera with the larger f/stop and lower ISO. More likely you will lose. All things equal (framing and DOF) the noise advantage goes to the larger FF sensor. With todays current cameras however the difference is pretty minor. You mentioned the Fuji X-T20. That camera uses Fuji's X-Trans CFA with a Sony sensor. The X-Trans design has a slight noise advantage over other APS cameras with Bayer CFAs and so that would lessen the discrepancy.

Joe


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## Derrel

Okay...a few things to research on the 'Net would be overall sensor performance, like from DxO Mark.com's web site. Let's be honest: the new-generation Sony-made sensors are industry-leading, and can shoot at High ISO levels with minimal noise, but MORE-IMPORTANTLY, they can be deliberately under-exposed on-scene, and then the raw files can have the dark, almost-black shadow and mid-tone areas "lifted" (brightened) in software, and a usable, good picture made from a two- or three- or even four-stop under-exposed original capture. Cameras that can do this are said to be ISO Invariant. There are some compact cameras that are ISO invariant, and the new Nikon, Sony, and Pentax d-slrs are ISO invariant: again, on-scene, you can deliberately speed up the shutter to stop motion, or you vcan close-down the lens to day, f/11, to get deep depth of field, make a severely under-ecposed picture, then brighten it in software later. This is a HUGE advantage, and not all brands or models of cameras can do this.

So...sensor performance/ISO invariance can allow you a huge settings advantage in bad,bad lighting. Next up would be lens speed, likie f/1.4 or f/2.0 or f/2.8, and of course, the right lenses for your needs.

Third is picture angle of view per focal length. This is the FACT: a smaller sensor creates MORE in-focus stuff PER PICTURE ANGLE of view than does a bigger sensor. For example, the iPhone's semi-wide angle lens has deep,deep,deep depth of field. A Nikon D5 and its Full-frame sensor with its semi-wide angle lens (28mm let's say) has only a "band of focus" at the 3 to 10 foot distance range at f/11, and then the background grows blurry. APS-C cameras are in the middle let's say. APS-C is VERY useful for many everyday, documentary photos, family and event shots, etc..

The advantage of APS-C cameras with fast primes, like the 56mm f/1.2 let's say from the Fuji X-system...that allows a guy to create SHALLOW DOF equivalence of say a Canon or Nikon and their 85mm f/1.2 or 85mm f/1.4 photos. But the shallow DOF equivalence so many people want is less-useful than the deeper DOF advantage that APS-C sized cameras create. I shot exclusively APS-C from 2001 to 2006, and still have APS-C. I think the answer is to buy a camera and lenses that YOU like to shoot. If you find yourtself shooting at ISO 12,800 a lot, it migth pay to have a couple very fast primes, f/1.4 models, for some shots, but still, lighting (OFF-camera flash, On-camera bounce flash, or LED supplementary lighting) might be worth looking in to for some types of shots, but not all.

There are plenty of VERY good APS-C cameras on the market these days.


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## Gary A.

enerlevel said:


> Hi thanks for the reply,
> Sorry for my confusing statement, I might have said it wrong...
> So basically for what I have noticed is that when shooting with similar focal lengths on apsc and full frame for example 23mm in apsc and 35mm on full frame, I can use a lower F stop to attain similar focus results..
> As an example, if I chose to shoot with the 28mm FF @f6 to get all my group shots in focus, then I might use f4 on apsc to get similar results. And because of this, I be using lower iso on apsc. Yes flash is option but sometimes it's hard to travel with a flash or use it in some places.
> 
> 
> 
> Derrel said:
> 
> 
> 
> I am not sure what you mean about needing "less depth of field" since you are mostly shooting groups.
> 
> The depth of field difference between FX sensor size and APS-C sensor size is somewhat noticeable at certain distances and at certain picture field of view distances; the differeces can add up. APS-C often pulklks the background into clearer focus than does FX, due to lens length choices that often arise with a group shot; often the APS-C shooter will be forced into using a short focal length lens, to make up for the "Crop Effect", and when he uses a 30 to 35mm lens length to GET a group of people into a picture framed up from 15,20,25 feet, the background on an APS-C shot comes into clear, recognizable focus to a higher degree than with FX.
> 
> You are discussing what has become known as "equivalence", but your comment about needing "less depth of field" for group shots is perplexing. ALSO, using a 28mm lens at IS 12,800 for group photos? That means you're shooting grouop shots under abysmally dim lighting. THis sounds like the type of situation where a new camer or a new lens is the last thing needed, and the first thing needed is ancillary lighting.
Click to expand...

Yes, some of the terms are not quite correct or precise.   

"Sorry for my confusing statement, I might have said it wrong...
So basically for what I have noticed is that when shooting with similar [equivalent or similar Field of Vision - FOV]  focal lengths on apsc and full frame for example 23mm in apsc and 35mm on full frame, I can use a lower F stop to attain similar focus [ Depth of Field - DOF] results..
As an example, if I chose to shoot with the 28mm FF @f6 to get all my group shots in focus, then I might use f4 on apsc to get similar results. And because of this, I be using lower iso on apsc. Yes flash is option but sometimes it's hard to travel with a flash or use it in some places."

There are a lot of various elements which affect DOF and the size of aperture and the size of your sensor/capture medium are two very important elements which will affect DOF. 

Generally, at identical apertures and equivalent FOVs, an APS-C sensor will deliver about a stop more DOF than a Full Frame sensor.  A similar DOF for a FF at F/5.6 would be F/4 for an APS-C.  

If there is any advantage to a lower ISO versus a larger sensor is dependant entirely upon your cameras, sensors and the manufacturers in-camera software.

Generally, a FF will deliver less noise than an APS-C sensor at similar ISOs. But my older FF Canon 1DsMKII has significantly more noise at ISO 6400 than my newer APS-C Fuji XT2 at 6400.

With the advance of noise reduction at elevated ISO, in a modern digital camera often noise and sensor size doesn't doesn't come into play until the image is enlarged. Example: At 11x14 and ISO 1600, there may not be any visible differences in noise between an APS-C and a FF.  But at 20x30, the viewer can see a difference. 

I am saying two things:
1)  There are a lot of variables to be considered; and
2) There is also a test for significance.  If all you are making are 4x6 prints, then there may not be any significance between an APS-C sensor at ISO 3400 or a FF at ISO 3400, but at 20x30 ... et cetera. 

Somewhere in my ramblings, I think I may have answered your question(s).  Remember that flashes come in all sizes and power, even a little fill-in flash may be helpful in a number of ways for ISO 3400 situations.


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## Solarflare

Assuming identical level of technology, the larger sensor will almost always give more image quality. Even in the worst case scenario, it still gives at least the same image quality as the smaller sensor.

Also, the optics are always in the "advantage" and have more influence on the final image quality than the sensor.



Gary A. said:


> Yes, some of the terms are not quite correct or precise.


 Please dont double quote what you already quoted.


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## enerlevel

Thanks for all the replies... Yes FF does have better noise performance and roughly about 1 stop advantage over apsc but in my case i am not using the same iso on both the system... as stated by few members, the apsc has ability to get "more in focus" with a lower F stop than a FF thus using a lower iso setting. 
Plus it's not the noise which is a problem for me as I don't print too big, it's the purple colour noise which has become a problem ... for example when using a6300 vs a7, there is too much of purple amp glow on a7


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## Gary A.

enerlevel said:


> Thanks for all the replies... Yes FF does have better noise performance and roughly about 1 stop advantage over apsc but in my case i am not using the same iso on both the system... as stated by few members, the apsc has ability to get "more in focus" with a lower F stop than a FF thus using a lower iso setting.
> Plus it's not the noise which is a problem for me as I don't print too big, it's the purple colour noise which has become a problem ... for example when using a6300 vs a7, there is too much of purple amp glow on a7


I believe you've answered your own question.


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## beagle100

enerlevel said:


> Thanks for all the replies... Yes FF does have better noise performance and roughly about 1 stop advantage over apsc but in my case i am not using the same iso on both the system... as stated by few members, the apsc has ability to get "more in focus" with a lower F stop than a FF thus using a lower iso setting.
> Plus it's not the noise which is a problem for me as I don't print too big, it's the purple colour noise which has become a problem ... for example when using a6300 vs a7, there is too much of purple amp glow on a7



yes, definitely avoid the "purple amp glow"
*www.flickr.com/photos/mmirrorless*


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## fmw

In general, shooting groups of people will put you far enough away from the group to produce fairly deep depth of field.  Perhaps you need to work hard on venue and background.


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