Tamron Still Believes in APS-C

Started 11 months ago | Discussions thread
nnowak Veteran Member • Posts: 7,764
Re: Tamron is leaving $ MONEY $ on the table not making EF-M, Fuji-X lens

Microprism wrote:

nnowak wrote:

Microprism wrote:

thunder storm wrote:

Microprism wrote:

Athunder storm wrote:

Microprism wrote:

nnowak wrote:

Microprism wrote:

nnowak wrote:

ihgold2 wrote:

dwfrommonterey wrote:

Not everyone care to upgrade to Fullframe, majority of "consumer" don't want to spend $2000 when an $500~$1000 APS-C DSLR or Mirrorless will do.

Canon RP with decent kit lens $999. Right now.

That's a really tempting offer. Do you think f/7.1 is limiting though, in that kit lens? IQ notwithstanding, seems like f/7.1 being the largest possible aperture would be frustrating. What does everyone think?

f/7.1 on full frame is equivalent to f/4.5 on Canon APS-C crop. Yes, f/7.1 sounds slow, but when you consider that an equivalent EF-M lens would need to be 15-66mm f/2.5-4.5, f/7.1 suddenly looks pretty good. Going the other way, the EF-M 15-45mm f/3.5-6.3 is equivalent to a full frame 24-72mm f/5.6-10. After converting for equivalence, the EF-M 15-45mm ends up a full stop slower than the RF 24-105mm f/4-7.1.

No, f/7.1 is not ideal for low light use, but it is still better than any of the existing EF-M zooms.

It is really slow in low light when your subject is moving and you need a faster shutter speed.

For the same noise levels, you will still get a faster shutter speed with the RF 24-105mm f/4-7.1 than any EF-M zoom.

I don't think noise and exposure level are interchangeable for most photographers, but suit yourself.

Fake response.

How about a real response then? I don't remember

You should remember someone posting this:


anyone ever posting, "Hey, that's great shot. Look at that low noise. Too bad the bird is a blur." If your subject is in motion you need a faster shutter speed to stop the motion unless you like blur. A faster lens allows that.

It's simply nonsense to state a faster lens is the only factor allowing for that. It can also be a higher ISO with a sensor with a better signal to noise ratio.

You either get the shot, or you don't.

You either understand how to adjust your ISO or you don't. You either understand the sensor signal to noise ratio performance is a factor just as important or you don't.

I don't think noise and exposure level are interchangeable for most photographers, but suit yourself.

Suit yourself.

I know quite well that no matter how good a sensor is there is some light level at which either you use a faster lens or you get distractingly visible noise. The better the sensor the lower the light level in which it performs acceptably, but that threshold always exists. For myself, I know exactly what ISO level on my own cameras is acceptable to me. That suits me fine.

That is exactly the point. The 24-105mm f/4-7.1 on full frame will give you a higher threshold than any EF-M zoom on crop.

If I follow you correctly


a full frame camera with a 105mm f/7.1 FF lens will produce an image with equivalent noise level to 66mm f/4.5 lens on a APS-C camera, correct?

not exactly

I think I got it, but here's the rub. If the correct exposure is f/4.5 and the actual exposure is f/7.1, the result is an underexposed image. So, next you take the full frame photo and go into your image editing program to brighten it accordingly. However, because the image was underexposed originally you have sacrificed an f/stop or more of dynamic range in order to compensate for the underexposure. So, yes, the 100mm FF f/7/1 setup has yielded an image with the noise level of a APS-C f/4.5 camera and lens combination. But it is one with less dynamic range. There is no free lunch in my experience. Of course, if f/7.1 is the correct exposure you are in great shape.

Let's back up. First, we need to clarify that we are talking about sensors from the same technological generation.  No original 5D vs M6 II.  Based on the differences in sensor size/area between full frame and Canon APS-C, we have the following....

  • At the same ISO setting, a full frame sensor will have 1 and 1/3 stops lower noise
  • At the same ISO setting, a full frame sensor will have 1 and 1/3 stops more dynamic range. 
  • At the same aperture setting, the full frame sensor will have 1 and 1/3 stops shallower depth of field.

ISO 2500 on a Canon crop camera will have the same noise levels and same dynamic range as ISO 6400 on the full frame sensor.  An aperture of f/4.5 on crop yields the same depth of field as f/7.1 on full frame.

An exposure of f/7.1, ISO 6400, and 1/100 on full frame versus f/4.5, ISO 2500, and 1/100 on crop will produce images with the same noise levels, the same dynamic range, the same depth of field, and the same subject motion blur.

The fastest zooms for the M system are f/5.6 at the long end.  Lets say you are at f/5.6, ISO 3200 and 1/100 with a crop camera.  At f/7.1 and 1/100 on the full frame camera, you would need to be at ISO 5000 for the correct exposure.  ISO 5000 is 2/3 of a stop above ISO 3200.  Given the 1 and 1/3 stop noise advantage for full frame, you are still left with a net advantage of 2/3 of a stop at ISO 5000.

Here's the short version.... even though f/7.1 is slower than f/5.6 or f/6.3, the full frame camera can boost the ISO to compensate and still produce an image with lower noise and more dynamic range.

Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow