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05-25-2018, 04:11 AM   #1
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which lens do I need?

I want to know which lens I need to buy in order to take a photo identical to the one at this link:
Male Happiness Stock Photo 787524319 - Shutterstock

original photo:

nikon D3400 APS-C
f stop 5.6
focal length 300
iso 180

I want to buy something like a 645D. I want to do photos similar to what is shown in the url above. what lens focal length do i need, or focal length and f stop?

what settings would you have used to take a similar photo, which lens and aperture?

thanks

05-25-2018, 04:32 AM   #2
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That's a portrait, and quite a "standard" one at that.


It was taken with a long focal lenght, because the distance between camera and subject has an impact on perspective, which the photographer must know about. Also varying aperture, distance and f.l. impacts DoF and background blur.


The first purchase I would suggest you is a couple of photography book: one covering the technical bases and another one on composition.
05-25-2018, 04:46 AM - 1 Like   #3
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Just about any camera with a wide-ish aperture lens could reproduce that effect.

There's more to it than you think. Learn more about photography and worry less about gear.
05-25-2018, 05:11 AM   #4
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my question is: if I were to buy a 645D camera, which lens would I buy to be able to shoot the same photo, and what settings would I use?

05-25-2018, 05:36 AM   #5
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If you want to reproduce a similar FOV and DOF with a 645D you need a 582mm lens set at F10.


In other words this lens: SMC Pentax-A* 645 600mm F5.6 ED [IF] Reviews - 645 Telephoto Primes - Pentax Lens Reviews & Lens Database


Kind of a pointless exercise though trying to recreate the image this way.
05-25-2018, 05:37 AM   #6
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QuoteOriginally posted by dtiberio Quote
my question is: if I were to buy a 645D camera, which lens would I buy to be able to shoot the same photo, and what settings would I use?
The camera used for that photo has an APS-C sensor, which has a crop factor of approximate 1.9x compared to the Pentax 645D's "medium format" sensor.

The focal length used on the original shot was 300mm (quite long for portraiture, I'd suggest), so the equivalent focal length on the 645D would be (approximately) 300 x 1.9 = 570mm, so let's say 600mm rounded up.

The aperture for the original shot was f/5.6, so the equivalent aperture on the 645D (using the focal length above) is 5.6 x 1.9 = 10.64, so around f/10 - f/11.

So, you'd be looking at a 600mm lens at f/11 on the 645D to get a shot with a similar field of view, perspective and background blur when taken at the same distance.

But there isn't a 600mm lens in production for the 645D. The longest is 400mm, and that's quite a beast of a lens. There is an older manual focus model available, however.

I believe the photo you've linked to was taken by you, given your user name here and the profile name on Shutterstock?

On that basis, I'd ask a question in return:

Is there a reason why you chose 300mm as the focal length for that shot? It's entirely your creative choice to do so, but that's rather a long focal length for portraiture that will lead to a significant flattening of features. That can be flattering and appealing in some cases, but I'd suggest that most portraiture on APS-C cameras is usually taken within the 50 - 135mm range. That would be equivalent to 95 - 256mm on the 645D, and there are several lenses within and near to that range currently available.
05-25-2018, 06:11 AM   #7
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you said: "Is there a reason why you chose 300mm as the focal length for that shot?"

I just bought the lens that month, and when I shoot, I will change my distance to the model every 50 shots or so to add variety to the photos. many of the photos are 150mm with the same lens. when closer, I can fill the shadows with onboard flash, when far, I have not been able to get the remote flash to fill properly yet, but I think I will have good results next shoot.

I am selling my photos as stock photography and I am hoping that if I take photos with a soft focus on the background, maybe I will make more money.

when I try to soften the background merely adjusting the aperture / iris, I do not think it looks as good as taking the photo from a distance.

I originally did this using the p900 at 2000mm but the camera is very hard to keep steady at a long distance even with a tripod.

05-25-2018, 07:12 AM   #8
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QuoteOriginally posted by dtiberio Quote
you said: "Is there a reason why you chose 300mm as the focal length for that shot?"

I just bought the lens that month, and when I shoot, I will change my distance to the model every 50 shots or so to add variety to the photos. many of the photos are 150mm with the same lens. when closer, I can fill the shadows with onboard flash, when far, I have not been able to get the remote flash to fill properly yet, but I think I will have good results next shoot.

I am selling my photos as stock photography and I am hoping that if I take photos with a soft focus on the background, maybe I will make more money.

when I try to soften the background merely adjusting the aperture / iris, I do not think it looks as good as taking the photo from a distance.

I originally did this using the p900 at 2000mm but the camera is very hard to keep steady at a long distance even with a tripod.
Instead of using a very long focal length and standing way back from your subject, try shooting at a shorter focal length - perhaps something in the 50 to 135mm range on APS-C - with a faster aperture (maybe f/2.8 - f/4), and position your model at a greater distance from the background. If you want an even more softened background and you can't achieve it with the aperture setting, keep moving your subject further and further away from the background until you get what you're looking for

Last edited by BigMackCam; 05-25-2018 at 07:28 AM.
05-25-2018, 07:21 AM   #9
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The larger the sensor the longer the lens you need for the same FOV from the same distance. Ofcourse you can go closer using wider apertures to get a similar effect. Your Depth of field will be much narrower though. Typically a professional photographer would use a 70-200 F2.8 lens on full frame for these kind of shots. You can also use those on APS-c you would be further away increasing your DOF, and at the same time enlarging the OOF blur effect. In general shooting with larger sensor your relative depth of field gets narrower and focus more critical.
05-25-2018, 07:53 AM - 1 Like   #10
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There's a huge difference between knowing what settings a person used, and why he used them. Typically for portraits long lenses are used to reduce the influence of messy back grounds. As focal length gets longer, the amount of background displayed is less and less.

But why do you want a 645D? A K-1 will do the same thing much easier. The difference in IQ will be minimal.

Stock agencies aren't going to buy your photo, just because they are taken with a 645D
05-25-2018, 08:14 AM   #11
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There is an FA 150mm f/2.8 lens available for the 645 system that costs about $1,250. It's not quite the same focal perspective as what you are looking for, but for practical purposes, it should give you great portraits in that same style. See examples here: Search: 645d 150mm | Flickr

There's also an FA 200mm f4 (about $1000), FA 300mm f4 ($4,300!!!!) and 400mm f/5.6 ($2,500) if you wish for something longer.
05-25-2018, 08:33 AM   #12
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you said: "position your model at a greater distance from the background"

at the time I was working within the restrictions of a city setting. now that I am in the suburbs I have more room to maneuver and will try to get the same effect with smaller focal range. I am starting to film in 2 weeks so I am probably going to skip the 645 series cameras.

---------- Post added 05-25-18 at 08:40 AM ----------

also this is another photo that I use the 300mm lens: Female Teen Girl Student Standing On Stock Photo 1081402829 - Shutterstock

I want to do more of those types of shots. is it possible to do so with a reasonable lens on the 645d?
05-25-2018, 09:31 AM - 1 Like   #13
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My recommendation would be a K-1 with the D FA* 70-200mm and/or a classic portrait lens, such as the FA 77mm Limited or the upcoming D FA* 85mm. The 645D is mostly obsolete by now and it will likely slow you down in a street photography setting.

In any case, to answer your question, you can use our lens finder tool to find any Pentax lens (current and legacy) as well as current third-party lenses. Here are 645 lenses:

Pentax 645 Lenses | PentaxForums.com

And here are full frame lenses:

Full Frame Lenses with Autofocus | PentaxForums.com

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05-25-2018, 12:34 PM   #14
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I'm not getting it...


In the first post you asked how to take a similar picture to one you linked, then you speak like you took the picture yourself.


But if you did, surely you would know how to do it again, even on another format..?
05-25-2018, 12:57 PM - 1 Like   #15
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QuoteOriginally posted by LensBeginner Quote
I'm not getting it...


In the first post you asked how to take a similar picture to one you linked, then you speak like you took the picture yourself.


But if you did, surely you would know how to do it again, even on another format..?
If I can summarise (and perhaps the OP can confirm)...

He was previously using a Nikon P900 bridge camera, and took shots at very long focal lengths - equivalent to 2000mm - from a distance, in order to create a blurred background. He since changed to a Nikon D3400 and either a prime or zoom lens at 300mm, set to f/5.6, again shooting from a distance, and creating that blurred background (as in the photo he linked to, which I believe is his). He's now potentially interested in moving to a Pentax 645D and wants to understand what equivalent lens and aperture setting he should use on this camera to get the same effect.

However, I'd respectfully suggest that there are options to explore other than using really long focal lengths, such as shooting closer to the subject with a shorter lens and using a combination of fast(ish) aperture and subject-to-background distance to get the same out-of-focus background style that he prefers. Field of view comes into play, as Norm suggested, but it seems to me like limiting one's self to shooting at very long focal distances may not be the best approach. Creative use of other factors should enable equally pleasing results without requiring such powerful lenses...
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