Need Advice on Lenses

[Hardrock]

This is what I know. My efs 18-55 on my 50d or 1.6 crop camera at 50mm has the same FOV as my ef 50mm f1.4 does on a FF 5d mkII. But my ef 50mm f1.4 does not have the same FOV as my 18-55 at 50mm on my 50d or 1.6 crop camera. That is why I said the 18-55 at 50 would not look the same as the ef 50 on the crop sensor. Im sorry for all the confusion and I will redue the test for myself this weekend. Thanks for all the input.

 

[Overread19]

Hardrock - zoom lenses don't have perfect measurements made on their zoom range - at least between their long and short distances and the markings on the barrel are only based upon common manufacture standards. So 50mm on the 18-55mm might be slightly different to the true 50mm that a 50mm lens gives. However its close enough to the 55mm end that it shouldn't be too far out

 

[Hardrock]

Ok I was pretty much wrong! I used a 7d on a tripod with a Canon EF 50mm f1.4 and a Canon EF-S 18-55 at 51mm due to I could never get the lens to read 50mm in the exif. Even a t 51mm the 18-55 is a little wider than the 50mm f1.4 but I think its more of a cheap zoom issue than actual FOV. The book and camera never moved I just swapped lens. I did a test a couple of months ago with a 5dmkii, 7d ,and canon 100mm macro.. On that test I found the 7d to have a smaller FOV than the 5d with the 100 macro. Which makes perfect sense , since the 7d has a smaller sensor and is using less of the lens so to speak. I previously thought that the ef-s lens gave you similar FOV when compared to its FF equivalent ie: 7d with efs 18-55 set at 18 and 5d with 16-35L set to 18 the image should be very similar if not the same. So what does not make sense to me now is if the ef 50mm on a crop sensor gives you a FOV of an 85mm on FF than why does the ef-s lens say 50mm when in reality its more like 85 on FF since the the efs 18-55(at 50mm) and ef 50mm look almost identical on a crop body. Does this even make sense to anyone else or have I lost my mind? Sorry for mass confusion I never use EF-S glass due to I did not want to have to buy all new glass once I got a FF. Thanks for clarification and all the input. Here are my two examples and I hope this was more helpful than harmful.

Canon 50mm f1.4

Canon 18-55 at 51mm

 

[Hardrock]

The lightbulb finally went off in my head. The ef-s lens is made to give you the same FOV as an EF lens on a crop body but if you move to full frame and want the same FOV you will need to multiply your EF-S lens by the crop factor 1.6. So the reality is your 18-55 EF-S lens on your crop camera is really a 28-88 mm FF equivalent. Thanks TPF and again sorry for the wrong information.

 

[Robin Usagani]

Yes.. but if you compare the two 18-55 on crop vs 28-88 on full frame, the 18-55 on crop will give you smaller object in the back (more distortion). So if you shoot someone laying down on the stomach looking straight to the camera and feet on the back, the 18-55 will give you smaller legs while 28-88 is slightly more proportional especially if you compare the 55 and 88. The head size will be somewhat identical but the shape is slightly different.

 

[DiskoJoe]

couple points....

full frame sensor: 50mm =50mm focal length
APS-c sensor: 1.5(lens length) = 1.5(50) = 75mm

I would recommend a 24-70 f2.8 L also if you have the cash. great lens. will do all that you want. or if you want a cheaper lens get a tamron 28-75 f2.8 or a tamron 17-50 f2.8. both are great for portraits and around $400. Sometimes you can find nice deals on used sigma lens on ebay too. i like sigma but it costs a grip new. If possible get the sigma with APO glass. UBER clarity. may distort colors though but that can easily be fixed in post.

 

[EquineArt]

Very interesting topic.
I have a question that could help both the poster and myself..
Is there a big noticeable difference between the 50 1.8 and the 1.4 (other than the price ofc) because the original poster seems to be on a budget, and so am I..
I already own the 50 1.8 and bought it when I had my xsi and it was a jawdropper upgrade in AF speed and image quality from the 18-55 kit lens.