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full frame over crop

Discussion in 'Talking Pictures' started by southonline, Jun 26, 2014.

  1. southonline

    southonline Well-Known Member

    I know that a crop sensor increases lens factor by 1.6 (Canon) so moving to a full frame means your efforts to get longer lenses will take a step backward by dropping the 1.6 factor

    But with the larger better sensor of a full frame recover this factor by offering a better quality image to crop further in? ... I do hope I'm making sense here ;o)
     
  2. TimHeath

    TimHeath Well-Known Member

    Yes. You could 'replicate' a crop sensor on a full frame camera by cropping in some 40% or so, it would produce the same image. Nikon full frame cameras provide an option to use the smaller area of sensor when using their DX (crop sensor) lenses on a full frame camera.
     
  3. southonline

    southonline Well-Known Member

    its not so much that I want to replicate it, I'm just wondering would a full frame image when "cropped" to 1.6 offer the same quality as a crop sensor thats not been cropped, therefor the full frame holding the same magnification factor as the crop, but with maybe a better quality image ?
     
  4. TimHeath

    TimHeath Well-Known Member

    The quality would then depend on the quality of the sensor but generally speaking a 24Mp full frame cropped would be the same as a 16Mp from a crop sensor camera (approx). There would be other factors but that would be the principle I think.
     
  5. southonline

    southonline Well-Known Member

    OK cheers Tim ...I'll have a think ;o)
     
  6. daft_biker

    daft_biker Action Man!

    Compare the resolution you can get out of a new FF with old APS-C....eg 5D2 with 40D.

    Then there's the size of the subject in the viewfinder....it should look bigger and be easier to place the focus on when filling more of the frame.
     
  7. mikeh201355

    mikeh201355 Well-Known Member

    Using Tim's example, a 24MP full framecropped would give you 10MP on the same area as a 16MP APS-C sensor (1.6 is the linear dimension, the area is 2.56).

    This means you have two factors in play: the FF camera has fewer pixels on the subject but those pixels are a higher quality than the APS-C pixels. Add to this, that you also need to consider the generation of the camera because sensor design and processor design have given significant changes in quality.

    This is of interest for me because I do a fair amount of bird photography and most of those images have to be cropped on APS-C so would also be cropped on FF, so do I trade in my 7D for a 5DIII... I have seen one website doing a very good comparison of these two cameras, cropping the 5DIII image to the same coverage as the 7D and it is a close-run thing between them. The 5DIII is a sensor one generation on from the 7D, but a cropped 5DII image vs 7D (same generation of sensor) may show different results.
     
  8. southonline

    southonline Well-Known Member

    cheers Guys ..

    Its one of the frustrations of going from crop to FF that your collection of lenses will loose the 1.6 factor and from reading comments here it would seem your not gaining much in the terms of quality by the time you re apply that crop.. But what about the noise level? knowing you can push the ISO higher means a tighter crop is more possible ?
     
  9. daft_biker

    daft_biker Action Man!

    The 70D is the Canon to get if you want resolution......although only just so I've not bothered to upgrade from my 7D either.

    I've been lucky enough to do my own comparisons with my own lenses on FF and crop and the crop wins by a fair bit when it comes to resolving detail....but then I'm using macro lenses and base ISO.
     
  10. 0lybacker

    0lybacker In the Stop Bath

    Hi south,

    Yes, you are & it makes sense to Nikon, too, with at least the D700 (and I guess the other F/f Ds) as there is a specific setting that applies the crop. Bit like the Panorama mode that appeared with some film compacts and continued into digital with picture ratios.

    You can never make a true comparison because there will always be a factor involved that is different.

    For your specific camera now you can do a test, especially if you have an image taken with your old crop sensor camera & lens* that you can closely replicate. If so, repeat the shot on F/f with lens and crop in PC to same picture area & compare. If Canon offer an 'in-camera crop' then do one of those two & see if there is any difference.

    Cheers,
    Oly

    *I can't remember what you have done bought/sold/PX-wise, whether you still have a crop-sensor camera or no. Obviously, if you still have C/s cam & lens you can do a side-by-side comparison which would be ideal.
     
  11. southonline

    southonline Well-Known Member

    this is the problem until you buy its something you can't test - I have the 7D and one of the frustrations I have is noise level as soon as you start pushing the ISO past 1000 and from reading a few other forums it seems to be the weakness of the 7D, however the 5D walks past those settings and a lot more - But, on the other hand by switching I loose the 1.6 factor
     
  12. PeteRob

    PeteRob Well-Known Member

    A basic reason to move to full-frame is to lose the 1.6 factor. It would be even better to be able affordably to go to 6x6 or 6x7 and get a better field of view for the focal length.

    I started (first digital camera) with a 5D in 2007 having been using medium format. I later went half-way house, unfortunately no longer possible, with a 1.3 crop factor camera to extend my effective telephoto focal length ranges. Compared with the 5D
    I noticeably miss the "wide" end when I am out and about much more than I appreciate the increase at the "long" end.


    For longer lenses indeed the cost increases enormously as focal length increases and the crop factor is useful, while the pixel density on the crop sensor is greater than that of the full frame, because you then get more detail resolution compared with cropping. Historically there was an increase in noise using the smaller sensor but the advances in technology have made this less an issue.

    It is quite a dilemma though if you use telephotos. A 300 mm F4 + 7D is a lot cheaper than a 500 mm F4 + 5D. I am however leaning to the view that, if you need an effective focal length of 500mm it is better to start saving ....
     
  13. southonline

    southonline Well-Known Member

    agree and sadly it means lenses like the 70-200 have far less a kick on the FF

    I suppose its a case of running with both, using the crop on bright days when you need the 1.6 and so can cope with lower ISO and the FF as a walkabout
     
  14. Roger Hicks

    Roger Hicks Well-Known Member

    Look at it in terms of number of pixels. On the one hand, the more pixels the better. On the other hand, bigger pixels are better. This is why you want lots of big pixels = a bigger sensor.

    Now consider the same number of pixels of the same size, on a sensor of the same quality. It doesn't matter whether those pixels represent the whole of a crop sensor or the middle (say) 40% of a 24x36 sensor -- which is why there's no sense in using both crop and 24x36 at the same time to get "more magnification" with a telephoto. You aren't getting more magnification: the lens gives the same size image either way.

    The only exception is if the smaller sensor is of much better quality than the bigger one, usually because it's a newer design. This is however comparatively rarely the case, because most manufacturers are likely to use their flagship sensor technology in their flagship (24x36) sensors.

    Cheers,

    R.
     
  15. TimHeath

    TimHeath Well-Known Member

    But why not use the FF and crop it for the same result?
     
  16. southonline

    southonline Well-Known Member

    Thanks Roger - interesting viewpoint and you bring a good point on the sensor as my current camera is 5 yrs old and 18mg over a new model and 23 mg - looking at that alone will recover the loss of the 1.6

    very true .... doh ;o(
     
  17. AlexMonro

    AlexMonro Old Grand Part Deux

    One point that I don't think anyone's mentioned, if you're thinking about upgrading a Canon crop sensor body to full frame, you probably won't be able to use your crop format (EF-S) lenses. The S in EF-S stands for "Short backfocus", which means that EF-S lenses project farther into the mirror box than EF lenses, and would foul the mirror of a full frame camera. Canon made the EF-S lenses mount incompatible with EF mount bodies to avoid damage.

    You might be able to use some third party crop lenses on a full frame body, but check carefully first!
     
  18. southonline

    southonline Well-Known Member

    Cheers Alex, I did consider this when I first started buying lenses so they are all L so no issue when upgrading to FF - I had in the back of my mind when buying the 7D that this could happen and did consider going straight to the 5D but wanted to make sure I would start enjoying photography again..and more so have the control to walk away from my office and get out - one of the worst things working for yourself at home is locking the office and walking away
     
  19. daft_biker

    daft_biker Action Man!

    It doesn't for me. If I'm out shooting with a FF Canon I end up shooting different things than I do with my 7D.

    IIRC you need about 48MP on FF to match the pixel density of the 7D.
     
  20. southonline

    southonline Well-Known Member

    do you not find if you push the ISO above 1000 the noise is bad ?
     

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