[ElJamoquio]

form the same distance and F stop to see which gave them more DoF.

Strawman.

[jsherman999]

That is essentially what I'm asking for too. However, after lugging around a D600 w/grip and 80-200mm f2.8, I can say this... I love my compact K5 kit.

That 70-200 2.8 is about equivalent to a 50-135 f/1.8 on aps-c. Maybe you should have considered the 70-200 f4, which is smaller and equiv to about 50-135 f/2.5. (Or - my personal choice - the 180 2.8.)

The D600 just isn't comfy, which is why I love my K5, its a smaller camera, but has a more solid feel. i think combining the two cameras would be amazing, and would be an instant buy for me.

At then end of the day there are two cameras I want from Pentax.

The aformentioned combo K5/D600, more AF for the AF freaks, and maybe add the modular components of the LX (viewscreens and focus screens...theres a unique selling system point).

Completely agree. I just think Pentax has the DNA in them to make something like that, to make a better, more attractive FF camera than either Nikon or Canon. Judging by how nice/sexy the K-5 is in comparison to it's peers (outside of AF perf.). This is why I just feel like there's so much missed opportunity...

.

[Ash]

Tamron 70-200 f/2.8 compared to what? a 50-135 f/2.8 that costs more? a 50-135 f/2 that doesn't exist?

I do understand your point. High end APS-C glass will be just as expensive, but again, generally speaking, the more glass, the higher the cost. FA Ltds still cost more than the DA Ltds. For some reason, the FA* 28-70, FA* 80-200 and FA* 85 are valued more than the DA* 16-50, DA* 50-135 and DA* 55 respectively. And there are other examples. But who cares? The important bit is that with higher end products, there will be more expense outlayed.

[bossa]

That's not entirely accurate... if you're assuming same FoV then you'd have to use a wider lens on APS-c. I did a test using a 50 mm lens and a 35 mm lens on an object with a ruler beside it. There were a number of issues. one, I couldn't focus close enough with the 50mm lens to even take the same picture. People who discuss equivalency tend to ignore this type of issue. So I had to move my camera back so the 50 mm could focus (which meant I didn't get the framing I wanted in either image, so quite simply stated, I couldn't even get the framing I wanted using the 50 mm on FF.) But I digress.

Using the 35 mm on APS-c and 50 on FF to simulate the same F0V, the 35 mm APS-c produced twice as much DoF, 12mm to 6mm. That's not an illusion, that's a practical observation and measurement. You can always tell the difference between someone who is deriving information from theory from someone who's done this type of testing, because the theory guys always overlook relevant data and deal in absolutes. Things like the different characteristics of the different lenses used to achieve the same FoV etc are never mentioned. They misrepresented the theory, because they didn't realize, theoretical anything has to be verified empirically to have any validity. A theory without practical verification and empirical evaluation is generally called a notion. Most of what passes for theory around here is in fact un-substantiated misrepresentations of known theories that are too narrow in their application to be much use in the real world.

This is one of the issues I only understood after I'd sold my Pentax gear.

For example:
APS-C: Pentax DA*55mm MFD = .45 meters
DOF @ f/1.4 @ 45cm = 3.79mm

Backing this lens off to a distance of 1262mm to match the view of the 85mm Sigma on FF ( 55mm APS-C equivalent to a 82.5mm FF lens)
DOF @ 1262mm @ f/1.4 = 29.83mm

Full Frame: Sigma 85mm MFD = 1.3 meters
DOF @ f/1.4 @ 1.3m = 19.65mm
DOF @ f/2.0 @ 1.3m = 28.70mm (APS-C f/1.4 has equivalent DOF of f/2 FF lens for equal FOV and distance to subject)

Moving the APS-C camera back to the point where the framing was the same for both systems obviously makes a big difference here but, clearly, there's no equivalence when shooting in the zone where the difference in the MFD of the two lenses is being exploited.

A 90mm Macro on FF would probably get closer and thus get the framing to match.

Full Frame 90mm Tamron f2.8 Macro
DOF @ f/2.8 @ 45cm = 4.2mm (close enough)

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Last edited by bossa; 04-09-2013 at 09:13 PM.

[jsherman999]

This is one of the issues I only understood after I'd sold my Pentax gear.

For example:
APS-C: Pentax DA*55mm MFD = .45 meters
DOF @ f/1.4 @ 45cm = 3.79mm

Full Frame: Sigma 85mm MFD = 1.3 meters
DOF @ f/1.4 @ 1.3m = 19.65

Clearly there's no equivalence here due to the difference in the MFD of the two lenses. A 90mm Macro on FF would probably get closer.

Full Frame 90mm Tamron f2.8 Macro
DOF @ f/2.8 @ 45cm = 4.2mm (close enough)

Yes, you're going to be at the mercy of any lenses' MFD on any format, but if you're shooting that close-in don't you usually want more DOF? Especially for macro? I feel like this ^^ is an academic limitation, but maybe you have need for less DOF at very close distances for something I'm not thinking of.

Norm was not happy with the close-focusing of that 50mm, but do you really need to get closer than this for non-macro situations? (note: that's not even MFD)



.
I think for me it's usually about subject isolation at distances more like:





.

[bossa]

I was doing a lot of shots at one point where I wanted to turn the backgrounds into more delineated abstractions an I found the 77mm was ideal for this at MFD. For portraits this is not an issue as you just proved. Great shots as usual Jay.

DA*55mm @ f/4

This was shot at f/4 and is about right for my purposes but it does depend on the size of the subject and distance of course.

DA*55 @ f/2


DA*200 @ f/3.2



A Macro lens on Full Frame would easily do the same job:
D800E & Sigma 150mm f2.8 OS Macro

[Wired]

That 70-200 2.8 is about equivalent to a 50-135 f/1.8 on aps-c. Maybe you should have considered the 70-200 f4, which is smaller and equiv to about 50-135 f/2.5. (Or - my personal choice - the 180 2.8.)



Completely agree. I just think Pentax has the DNA in them to make something like that, to make a better, more attractive FF camera than either Nikon or Canon. Judging by how nice/sexy the K-5 is in comparison to it's peers (outside of AF perf.). This is why I just feel like there's so much missed opportunity...

.

I bought the 80-200 2.8. About $1000. And I went for 2.8 for the low light capabilities not the depth of field capabilities. So the f4 would not have met my needs.

[bossa]

Yes, you're going to be at the mercy of any lenses' MFD on any format, but if you're shooting that close-in don't you usually want more DOF? Especially for macro? I feel like this ^^ is an academic limitation, but maybe you have need for less DOF at very close distances for something I'm not thinking of.

Norm was not happy with the close-focusing of that 50mm, but do you really need to get closer than this for non-macro situations? (note: that's not even MFD)



.
I think for me it's usually about subject isolation at distances more like:





.

Love your work Jay.

The last shot would be your 180mm right?

[jsherman999]

Love your work Jay.

The last shot would be your 180mm right?

Yes, that one was the 180 @ 2.8. About the equivalent of a 120mm @ f/1.8 on aps-c. Truth be told my 77ltd wide-open gives a very similar look to that, including bokeh, I just need to move in a little closer with the 77 to get the tighter framing.

I find that you start to like a lens (in any format, any mount) you 'learn' that lens and then it just feels so natural to see and shoot with.... and you almost start to depend on it, because you 'see' so well at that FL and FOV and DOF. I'm like that with the Nikon 50, 180, the Pentax 77, the DA 35 and the DA 15, maybe the Nikon 20 2.8. I find it hard to shoot with other lenses now, those feel like all I need.

[bossa]

Yes, that one was the 180 @ 2.8. About the equivalent of a 120mm @ f/1.8 on aps-c. Truth be told my 77ltd wide-open gives a very similar look to that, including bokeh, I just need to move in a little closer with the 77 to get the tighter framing.

I find that you start to like a lens (in any format, any mount) you 'learn' that lens and then it just feels so natural to see and shoot with.... and you almost start to depend on it, because you 'see' so well at that FL and FOV and DOF. I'm like that with the Nikon 50, 180, the Pentax 77, the DA 35 and the DA 15, maybe the Nikon 20 2.8. I find it hard to shoot with other lenses now, those feel like all I need.

Thanks for replying. I can't say I'm at that level of familiarity yet but I'll get there eventually as long as I don't keep jumping systems.

I don't think I've ever made an image like that one of your son (last one) but I'll keep working on it. I don't have model's other than my cats at the moment so it's a bit different for me re' scale etc.

[Ash]

The 77/1.8 is definitely special, and would be a true wonder back on a FF body, and I think there are others Pentax have that can reproduce this kind of magic: D/FA 100/2.8 macro, 31/1.8, 85/1.4 and 135/1.8 to name a few.

[Uluru]

Completely agree. I just think Pentax has the DNA in them to make something like that, to make a better, more attractive FF camera than either Nikon or Canon. Judging by how nice/sexy the K-5 is in comparison to it's peers (outside of AF perf.). This is why I just feel like there's so much missed opportunity...

As we speak, Pentax is working hard to build up AF performance, build serious muscles and stamina, to meet the red bomber (Canon) and yellow danger (Nikon) and overtake them. It something as dramatic and as original as this, as only Pentax can pull out:

You Tube

You Tube

[RonHendriks1966]

This is one of the issues I only understood after I'd sold my Pentax gear.

For example:
APS-C: Pentax DA*55mm MFD = .45 meters
DOF @ f/1.4 @ 45cm = 3.79mm

Backing this lens off to a distance of 1262mm to match the view of the 85mm Sigma on FF ( 55mm APS-C equivalent to a 82.5mm FF lens)
DOF @ 1262mm @ f/1.4 = 29.83mm

Full Frame: Sigma 85mm MFD = 1.3 meters
DOF @ f/1.4 @ 1.3m = 19.65mm
DOF @ f/2.0 @ 1.3m = 28.70mm (APS-C f/1.4 has equivalent DOF of f/2 FF lens for equal FOV and distance to subject)

Moving the APS-C camera back to the point where the framing was the same for both systems obviously makes a big difference here but, clearly, there's no equivalence when shooting in the zone where the difference in the MFD of the two lenses is being exploited.

A 90mm Macro on FF would probably get closer and thus get the framing to match.

Full Frame 90mm Tamron f2.8 Macro
DOF @ f/2.8 @ 45cm = 4.2mm (close enough)

I wonder how this would be on an APS-H sensor!

The lens to compare with the DA*55 on aps-c and 85mm on FF, is offcourse the DA70mmLtd. Probably somewhere inbetween the 19,65mm and the 29,83mm wich would match up for some perfection

[Rondec]

Tamron 70-200 f/2.8 compared to what? a 50-135 f/2.8 that costs more? a 50-135 f/2 that doesn't exist?

If you want to take picture 'A', a hypothetical lens for a 36MP FF camera will at most cost exactly the same as the same lens on a 16MP APS-C camera. You just crop and use the same lens. I've chosen the MP so you can't really argue, but in practice, in my experience, it's the same for 24MP FF and 16MP APS-C.

On the wide scale, the full-frame lenses are much cheaper for the same functionality... look at 24-35mm f/1.4 costs and compare them to costs of 35-50mm f/1.4. Look at 24-75ish F/4 zoom lenses and compare them to 16-50ish F/2.8 lenses.

The FF lenses in these comparisons are always at least slightly faster, and are almost always some combination of a wider zoom range, smaller lens, and cheaper cost.

I've done this comparison at least five times on this website alone, if you want to search my name.

You are comparing a Tamron 70-200 lens to a (currently over priced) Pentax lens. Back in the day, the 50-135 routinely sold for 750 to 800 dollars and at that price, the question was a lot bigger as to which you would have. But, you have to remember that we are talking about Pentax and if they came out with a full frame camera, your 70-200 f2.8 lens is going to cost 2000 dollars plus. Guaranteed.

[normhead]

More DOF control, not "more DOF." Did you read somebody wrong?

No, some dude on here awhile ago had a bunch of spread sheets proving that FF had both shallower DoF but more DoF based on some crazy spreadsheets someone cooked up. Something to do with the level of magnification you need to make APS-c the same size as FF. It was total hogwash. But even saying more control is somewhat problematic. If you have the same number of F stops on two lenses you have the same amount of control. You may not have the same level of control in the shallow end, but that's different from having more control all together. Obviously, an APS-c at at f 32 in the long end has more DoF than an FF using the equivalent F0V. There isn't more control in one or the other it's just shifted a bit towards more DoF, away from shallow DoF.