Longer Lens or Crop Sensor

[john.margetts]

Photoflyer: Can your FF shoot in crop mode using the FF lenses?

Not on a Canon. There is no need as the 'DX' lenses (EF-S in Canon speak) will not fit on a full frame camera.

 

[BananaRepublic]

addition to the extra "reach"

extra reach is a marketing ploy, did you not read the thread.

 

[snowbear]

Photoflyer: Can your FF shoot in crop mode using the FF lenses?

Not on a Canon. There is no need as the 'DX' lenses (EF-S in Canon speak) will not fit on a full frame camera.

Ah, I think I remember reading that earlier.

 

[photoflyer]

extra reach is a marketing ploy, did you not read the thread.

Yes, I started it. I think we all know what we want to achieve when we use a given lens on a crop sensor camera versus a full frame. While I would like to have a 400 mm prime I cannot justify the 5k+ for the L series glass. I need another body so I will get the best Canon crop sensor I can and use my 70-200mm 2.8 USM mII it. (I also have the 2x teleconverter). Not as good as a prime on full frame but gets me another body and close to 400mm 2.8 without spending more than twice as much. As far as the semantics, I will leave them to others who have much more technical knowledge than I.

 

[Braineack]

Cropping an image to be pseudo 500mm isnt yielding the same definition as a native 500mm lens, whether for fx or dx.

what if you don't have to crop the DX image to appear as 500mm native FX?

 

[BananaRepublic]

extra reach is a marketing ploy, did you not read the thread.

Yes, I started it. I think we all know what we want to achieve when we use a given lens on a crop sensor camera versus a full frame. While I would like to have a 400 mm prime I cannot justify the 5k+ for the L series glass. I need another body so I will get the best Canon crop sensor I can and use my 70-200mm 2.8 USM mII it. (I also have the 2x teleconverter). Not as good as a prime on full frame but gets me another body and close to 400mm 2.8 without spending more than twice as much. As far as the semantics, I will leave them to others who have much more technical knowledge than I.

A 2.8 becomes a 4.48 when you factor in the crop on a canon which is 1.6

 

[photoflyer]

A 2.8 becomes a 4.48 when you factor in the crop on a canon which is 1.6

I am not sure I understand. I just put the 70-200 2.8 on a T5 I have and it shows f2.8.

 

[Overread]

A 2.8 becomes a 4.48 when you factor in the crop on a canon which is 1.6

I'd be VERY careful how you phrase some statements to avoid causing confusion.

The aperture in terms of exposure is the same no matter the camera body behind a lens. f2.8 is always f2.8 in exposure terms. This is a proven and well known bit of info that we all know without realising - because external light meters do work for any format (sensor) size and yet never require the sensor/film size to be entered in.

Now in terms of depth of field you are correct, the difference in depth of field between a 1.5 or 1.6 crop camera and a 35mm is roughly similar to around 1 stop in aperture. The full frame camera will have the lesser amount of depth of field.

An extreme way to also show this is if you use a mobile phone camera, where the sensor is tiny. In those you can easily see that the photos often have very large depth of field; indeed its often very hard to get background blurring with such a tiny sensor.

The other end of the extreme is medium format cameras which offer far more background blurring effect, again because the depth of field for the larger sensor/film is so much greater.

 

[john.margetts]

Nah Overread you are wrong. Sorry. Try it: fx body and dx body, same lens, aperture priority. Faster shutter speed on the fx than dx. As i say also, Pentacon 4/50 wide open on fx gathers f/2 speed.

Absolutely not. The whole point of stating apertures as a ratio is that a given aperture ratio allows the same amount of light through regardless of lens focal length and sensor size.

If you think about it, the light has to go through the lens before it hits the sensor - it cannot 'know' before hand what sensor it is going to reach or if it is going to reach a sensor at all.

I have used various sensor sizes over 45 odd years and in a given light condition, all lenses at a given aperture ratio (f/number) require the same shutter speed. My hand held light meter would not (could not) work otherwise.

Sent from my A1-840 using Tapatalk

 

[espresso2x]

You are right. Overread is correct. I just ran a test and the speeds are identical in both cases. I admit im mistaken and deleted the post.

 

[john.margetts]

Vignetting is where the edge of the lens is slower than the centre.

Again, absolutely not.

First, the edge of the image is not formed by the edge of the lens. All parts of the lens form all parts of the image.

Second, vignetting is caused by 'stretching' a spherical image to fit onto a flat surface. This is also why the edge of the image is less sharp than the centre.

Sent from my A1-840 using Tapatalk

 

[Braineack]

Cropping an image to be pseudo 500mm isnt yielding the same definition as a native 500mm lens, whether for fx or dx.

what if you don't have to crop the DX image to appear as 500mm native FX?

A 300mm fx lens on a dx camera is a lesser mag power than a 450mm fx on an fx camera no?

A 300mm FX lens on a DX camera, would appear exactly like shooting a 450mm lens on a FX camera.

So if you only had a 300mm, and you wanted more reach, you'd obviously shoot with it on the DX body.

If you say used a D750 with 24MP, and the 300mm, you'd have to crop the image down to appear like 450mm -- you'd have to crop it down to ~10.3MP.

If you say used a D610 with 24MP, and the 300mm, you'd have a full 24MP on an image with the same FOV as a 450mm on a FX.

 

[Braineack]

A 2.8 becomes a 4.48 when you factor in the crop on a canon which is 1.6

I'd be VERY careful how you phrase some statements to avoid causing confusion.

The aperture in terms of exposure is the same no matter the camera body behind a lens. f2.8 is always f2.8 in exposure terms. This is a proven and well known bit of info that we all know without realising - because external light meters do work for any format (sensor) size and yet never require the sensor/film size to be entered in.

Now in terms of depth of field you are correct, the difference in depth of field between a 1.5 or 1.6 crop camera and a 35mm is roughly similar to around 1 stop in aperture. The full frame camera will have the lesser amount of depth of field.

An extreme way to also show this is if you use a mobile phone camera, where the sensor is tiny. In those you can easily see that the photos often have very large depth of field; indeed its often very hard to get background blurring with such a tiny sensor.

The other end of the extreme is medium format cameras which offer far more background blurring effect, again because the depth of field for the larger sensor/film is so much greater.

this.

a 70-200 2.8 shot at 100mm and f/2.8 on a micro 4/3 (2x crop), would produce an image that appears like a FX shooting at 200mm and f/5.6 -- all other things being equal.

 

[Overread]

The difference in angle of view is exaggerated at shorter focal lengths. It's why we quickly go from 300 to 400 to 500 whilst at the shorter end there's a marked difference between 18mm and 16mm.

There is likely some difference between focal lengths in terms of the distortion and such between long focal lengths, but chances are the differences are more minor. The kind you have to really look for and the kind very quickly and easily removed by "lens corrections" clicks in editing software (eg Lightroom). So such differences might be very tricky to spot.

So for all extents and purposes most people compare the "reach" or magnification that long focal length lenses give rather than other aspects.

 

[BananaRepublic]

I do like throwing a ferret in a chicken house at times ( metaphorically)

But to follow on there is allot of confusing information been put out there take the clip below how much of that is true and how much of it is him trying to flog his brand.