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12-31-2015, 02:02 PM   #1
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DFA 150-450 is 230-690mm on APS-C?

I've read through a bunch of threads on the 150-450 and it's on my long term wish list. I guess I've just never seen mention of it's APS-C equivalence of 230-690mm. But, I was watching a video today and even looked at Ricoh's website and it lists it right there. I tried to search the forums but I didn't really see any mention of this.

I've seen many comparisons to the DA* 300 and even comparisons with the DA* 300 and 1.4TC to the 150-450 but in reality they aren't even close as far as reach goes are they? The DA* 300 is an APS-C lens so even with the TC its reach is now 420mm, correct? Where as the 150-450 is stated as being 230-690mm on APS-C and if you pair that with the TC it creeps up to just under 1000mm.

Now, I will fully admit that I try to get my head around the whole FF versus APS-C and focal view equivalence thing but sometimes it goes around and around in my head so much that I probably end up confusing myself more in the end than I was at the beginning. That poor little hamster running in my head at full speed misses a step and must gets taken for a ride much like this:

https://youtu.be/YXRH50fvHWA?t=31

Anyway, please set me straight on all of this. Am I reading into this completely wrong?

12-31-2015, 02:06 PM   #2
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No. It's a 150-450.

Focal length is focal length. Forget you ever heard the term "35mm equivalent".
12-31-2015, 02:08 PM   #3
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QuoteOriginally posted by colonel00 Quote
I've read through a bunch of threads on the 150-450 and it's on my long term wish list. I guess I've just never seen mention of it's APS-C equivalence of 230-690mm. But, I was watching a video today and even looked at Ricoh's website and it lists it right there. I tried to search the forums but I didn't really see any mention of this.

I've seen many comparisons to the DA* 300 and even comparisons with the DA* 300 and 1.4TC to the 150-450 but in reality they aren't even close as far as reach goes are they? The DA* 300 is an APS-C lens so even with the TC its reach is now 420mm, correct? Where as the 150-450 is stated as being 230-690mm on APS-C and if you pair that with the TC it creeps up to just under 1000mm.

Now, I will fully admit that I try to get my head around the whole FF versus APS-C and focal view equivalence thing but sometimes it goes around and around in my head so much that I probably end up confusing myself more in the end than I was at the beginning. That poor little hamster running in my head at full speed misses a step and must gets taken for a ride much like this:

https://youtu.be/YXRH50fvHWA?t=31

Anyway, please set me straight on all of this. Am I reading into this completely wrong?
Focal length never changes. If it says 150-450mm on the lens, that's what you get, regardless of the format.

On APS-C the field of view is narrower than on full frame.

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12-31-2015, 02:24 PM   #4
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I'm trying to hear ya. Though the hamster is still spinning in his wheel I get that the focal length doesn't change but it's the equivalent view and crop factor thing that get's me. I guess what is also confusing me is from when I had a Q and (at least I recall) it was commonly accepted that a 300mm lens on the Q had an equivalent view of 1650mm or whatever. We're dealing with the 5.6x crop factor versus FF, right? I guess this is where the disconnect occurs because wouldn't the same apply to the APS-C's 1.5x crop factor?

Also, what is the purpose of Ricoh making this statement then?

QuoteQuote:
3X ratio supertelephoto zoom (eq to 230-690 for APS-C)
Is that saying that on the forthcoming FF, when shot in APS-C crop mode it would have that equivalence?

12-31-2015, 02:41 PM   #5
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i don't think anything you've said is incorrect. it took me a while to just drop the idea of "35mm equivalence". It's only useful if you're comparing different formats. Get used to one format and the field of view for that format.

QuoteOriginally posted by colonel00 Quote
Is that saying that on the forthcoming FF, when shot in APS-C crop mode it would have that equivalence?
that's correct, but i don't know if i'd use the word "equivalence". the image circle should project on the sensor to cover the full frame, but if used in crop mode, you're cropping to keep only the center of the picture. the field of view that you're getting in the cropped picture will be more narrow.
12-31-2015, 02:54 PM - 2 Likes   #6
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The red rectangle is what a 35mm sensor would see. The blue rectangle is what an APS-C sensor would see. That's the 'crop factor'. That's it.

If you crop the 35mm picture to the APS-C size the pictures will be identical.
12-31-2015, 02:54 PM   #7
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Ok, the little hamster is starting to slow down now and logic is making sense again.
12-31-2015, 03:06 PM - 1 Like   #8
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If you plan to shot more than one format...

QuoteOriginally posted by colonel00 Quote
I've read through a bunch of threads on the 150-450 and it's on my long term wish list. I guess I've just never seen mention of it's APS-C equivalence of 230-690mm. But, I was watching a video today and even looked at Ricoh's website and it lists it right there. I tried to search the forums but I didn't really see any mention of this.

I've seen many comparisons to the DA* 300 and even comparisons with the DA* 300 and 1.4TC to the 150-450 but in reality they aren't even close as far as reach goes are they? The DA* 300 is an APS-C lens so even with the TC its reach is now 420mm, correct? Where as the 150-450 is stated as being 230-690mm on APS-C and if you pair that with the TC it creeps up to just under 1000mm.

Now, I will fully admit that I try to get my head around the whole FF versus APS-C and focal view equivalence thing but sometimes it goes around and around in my head so much that I probably end up confusing myself more in the end than I was at the beginning. That poor little hamster running in my head at full speed misses a step and must gets taken for a ride much like this:

https://youtu.be/YXRH50fvHWA?t=31

Anyway, please set me straight on all of this. Am I reading into this completely wrong?
The FOV changes when you use the same lens on different formats. So for example, if that 150-400 is an aps-c lens, to get the same FOV on FF you would need a 230-690mm zoom on FF.

This doesn't mean smaller formats have more 'reach' with the same lenses, it just means that it's being cropped more when you use the same lens on smaller formats.

So the focal length can never physically change, but it's highly misleading to say "focal length is focal length, full stop" because the same focal length on different formats gives you radically different images. (I wish people would move on from that almost-useless answer of 'focal length is focal length'. It only applies if you shoot one format your entire life )

The question you ask is valid and understanding at least the crop factor and maybe it's big-brother 'equivalence' is useful if you intend to shoot more than one format and not be befuddled while doing so.

If you only ever plan to shot one format - don't worry about crop factor, it doesn't directly apply to you.

.

12-31-2015, 03:25 PM   #9
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Alright, I'm getting my head around it now. I don't know why this threw me for so much of a loop.
12-31-2015, 03:55 PM   #10
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There are two issues raised by the original post that have not been answered directly. The 300 f4 with the 1.4TC will have a "focal length" of 420mm, and on an APS-C SLR will frame like a 630mm lens, pretty close to the long end of the150-450 without the TC. The 300mm f4 with the TC will have a focal ratio of 5.6, and will autofocus on a Pentax SLR. The 150-450 is f4.5-5.6. Put the 1.4 TC on that one and it becomes something like f5.6-6.7. It may still autofocus at the long end, but it will be hit or miss.
12-31-2015, 04:24 PM   #11
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QuoteOriginally posted by mechmike10 Quote
It may still autofocus at the long end, but it will be hit or miss.
When I was using the 55-300 with a 1.4 TC the AF only struggled in very poor light. And that was F/5.8 at the long end.
12-31-2015, 04:28 PM   #12
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Every now and then my dad gets this wonky in his head. The key to remember is this. The lens focal length isn't affected by the platform it is designed for - and the field of view is mostly a property of the focal length and the design (so a 17mm fisheye is not the same as a 17mm regular wide angle) and the "window" upon which the image is being projected. What's important is that the larger size image circles of lenses designed for larger formats don't get used on smaller formats they are tossed aside. So a 300mm 8x10 camera lens and a 300mm lens native to the tiny Q would give virtually the same field of view on the Q. The Q lens on the 8x10 would look like a tiny crop out of the 8x10 image since the lens would not cover the entire area needed but that area illuminated would look similar to what you would get from the native lens if you cut down the image to that tiny portion.

Boriscleto's earlier picture is very helpful to conceptualize this. Another way is to imagine you are sitting in a house looking out at the world. You cannot move from the chair you are in but you can have different size windows put up. The smallest window is like small sensor, the giant picture window like an 8x10 camera. The view you see changes based on the amount masked off by the window - the sensor in a camera is like this window. Granted the example is a bit different due to the projection vs. view through aspect but it helps my dad when I say it.
12-31-2015, 08:01 PM   #13
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QuoteOriginally posted by boriscleto Quote

The red rectangle is what a 35mm sensor would see. The blue rectangle is what an APS-C sensor would see. That's the 'crop factor'. That's it.

If you crop the 35mm picture to the APS-C size the pictures will be identical.
Arenal Volcano?
12-31-2015, 08:35 PM   #14
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I think the source of your confusion is the (incorrect) assumption that a DA lens would have a different field of view from an FA (or DFA) lens of the same focal length when mounted on an APS-C camera.

They wont.

The DA*300 on APS-C gives the same field of view as a 450mm lens on full frame. Just as would an FA300 on APS-C. They will both be identical on the Q too.
The DA*300 + 1.4xTC will give you very nearly the reach of the DFA150-450, with less bulk, but also less versatility....
01-01-2016, 12:11 PM   #15
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QuoteOriginally posted by CRPhoto Quote
Arenal Volcano?
I don't know. I just took the graphic from Wikipedia...
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